U.S. patent application number 17/053088 was filed with the patent office on 2021-05-13 for methods for logical channel prioritization and traffic shaping in wireless systems.
This patent application is currently assigned to IDAC HOLDINGS, INC.. The applicant listed for this patent is IDAC HOLDINGS, INC.. Invention is credited to Faris Alfarhan, Paul Marinier, Ghyslain Pelletier.
Application Number | 20210144580 17/053088 |
Document ID | / |
Family ID | 1000005359765 |
Filed Date | 2021-05-13 |
![](/patent/app/20210144580/US20210144580A1-20210513\US20210144580A1-2021051)
United States Patent
Application |
20210144580 |
Kind Code |
A1 |
Alfarhan; Faris ; et
al. |
May 13, 2021 |
METHODS FOR LOGICAL CHANNEL PRIORITIZATION AND TRAFFIC SHAPING IN
WIRELESS SYSTEMS
Abstract
A method performed by a WTRU may comprise associating a logical
channel with a plurality of token buckets, including at least a
long term token bucket and a short term token bucket. The method
may further comprise transmitting logical channel data on the
associated logical channel, in a TTI. The transmitted logical
channel data of the TTI may be no larger than a value corresponding
to a minimum of the long term token bucket and the short term token
bucket. The long term token bucket may be initialized to a value
which is greater than an initialized value of the short term token
bucket. When the WTRU transmits logical channel data in a TTI, the
WTRU may decrement the long term token bucket and the short term
token bucket by a total size of one or more MAC SDUs served on the
associated logical channel.
Inventors: |
Alfarhan; Faris; (Montreal,
CA) ; Marinier; Paul; (Brossard, CA) ;
Pelletier; Ghyslain; (Montreal, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
IDAC HOLDINGS, INC. |
Wilmington |
DE |
US |
|
|
Assignee: |
IDAC HOLDINGS, INC.
Wilmington
DE
|
Family ID: |
1000005359765 |
Appl. No.: |
17/053088 |
Filed: |
May 8, 2019 |
PCT Filed: |
May 8, 2019 |
PCT NO: |
PCT/US2019/031282 |
371 Date: |
November 5, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62668585 |
May 8, 2018 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 47/215 20130101;
H04W 80/02 20130101; H04W 76/27 20180201; H04W 28/0268 20130101;
H04W 72/14 20130101 |
International
Class: |
H04W 28/02 20060101
H04W028/02; H04L 12/819 20060101 H04L012/819; H04W 72/14 20060101
H04W072/14; H04W 76/27 20060101 H04W076/27; H04W 80/02 20060101
H04W080/02 |
Claims
1-20. (canceled)
21. A method performed by a wireless transmit/receive unit (WTRU),
the method comprising: receiving a radio resource control (RRC)
configuration message indicating that a logical channel (LCH) is
associated with a first bucket and a second bucket; increasing the
first bucket at a rate corresponding to a first prioritized bit
rate (PBR) when the first bucket is not full and increasing the
second bucket at a rate corresponding to a second PBR when the
second bucket is not full; receiving an uplink (UL) grant;
transmitting data on the LCH, the data being no larger than the
minimum of a value corresponding to the first bucket and a value
corresponding to the second bucket; decrementing the first bucket
and the second bucket, by an amount of data transmitted on the
LCH.
22. The method of claim 21, wherein the first PBR is different than
the second PBR.
23. The method of claim 21, wherein the first bucket has a
different bucket update period than the second bucket.
24. The method of claim 21, wherein the first bucket has a
different accumulation rate than the second bucket.
25. The WTRU of claim 21, wherein the first bucket and the second
bucket are used in all steps of a logical channel prioritization
(LCP) procedure.
26. The method of claim 21, wherein the UL grant is received from a
base station.
27. The method of claim 21, wherein the decrementing is in
accordance with a total number of media access control service data
units (MAC SDUs) transmitted on the LCH.
28. A wireless transmit/receive unit (WTRU) comprising: circuitry
configured to increase a first bucket at a rate corresponding to a
first prioritized bit rate (PBR) and increase a second bucket at a
rate corresponding to a second PBR; a receiver configured to
receive an uplink (UL) grant; a transmitter configured to transmit
data on a logical control channel (LCH) associated with the first
bucket and the second bucket, the data being no larger than the
minimum of a value corresponding to the first bucket and a value
corresponding to the second bucket; circuitry configured to
decrement the first bucket and the second bucket, by an amount of
data transmitted on the LCH.
29. The WTRU of claim 28, wherein the first PBR is different than
the second PBR.
30. The WTRU of claim 28, wherein the first bucket has a different
bucket update period than the second bucket.
31. The WTRU of claim 28, wherein the first bucket has a different
accumulation rate than the second bucket.
32. The WTRU of claim 28, wherein the data is device to device
(D2D) data and transmitted to another WTRU.
33. The WTRU of claim 28, wherein the UL grant is received from a
base station.
34. The WTRU of claim 28, wherein the amount of data is in
accordance with a total number of media access control service data
units (MAC SDUs) transmitted on the LCH.
35. The WTRU of claim 28, wherein the receiver is configured to
receive a radio resource control (RRC) configuration message
indicating that the LCH is associated with the first bucket and the
second bucket.
36. A wireless transmit/receive unit (WTRU) comprising: a receiver
configured to receive an uplink (UL) grant; a transmitter
configured to transmit data on a logical channel (LCH) associated
with a first bucket and a second bucket, the data being no larger
than the minimum of a value corresponding to a first bucket and a
value corresponding to a second bucket; circuitry configured to
decrement the first bucket and the second bucket, by an amount of
data transmitted on the LCH.
37. The WTRU of claim 36, further comprising: the receiver
configured to receive a radio resource control (RRC) configuration
message indicating that the LCH is associated with the first bucket
and the second bucket.
38. The WTRU of claim 36, further comprising: circuitry configured
to increase the first bucket at a rate corresponding to a first
prioritized bit rate (PBR) and increase the second bucket at a rate
corresponding to a second PBR, wherein the first PBR and second PBR
are different.
39. The WTRU of claim 36, wherein the first bucket has a different
bucket update period than the second bucket.
40. The WTRU of claim 36, wherein the first bucket has a different
accumulation rate than the second bucket.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/668,585, filed May 8, 2018, the contents of
which are incorporated herein by reference.
BACKGROUND
[0002] In some wireless systems, high-priority or delay-critical
transmissions may negatively impact cell capacity as high-priority
devices may transmit more data than is expected by a network. This
may have an effect on access control, for example, by negatively
impacting the number of devices which may be supported. Quality of
service (QoS) enforcement for flows of a similar or lower priority
may also be negatively impacted since the high-priority devices may
take more than their expected share of network resources.
[0003] In 3rd Generation Partnership Project (3GPP) long term
evolution (LTE), radio bearers are served in order of their
priority. Using logical channel prioritization (LCP), data from a
logical channel having a highest priority is the first data which
may be included in a medium access control protocol data unit (MAC
PDU). Subsequently, lower priority data is included in the MAC PDU
until the MAC PDU size is either completely filled or until there
is no more buffered data remaining to transmit. The process of
filling a MAC PDU is performed in three steps (steps 1-3). In step
1, all logical channels which have a bucket variable (B) for a
logical channel j (Bj) which is non-empty are allocated resources
in decreasing priority order. In step 2, Bj is decremented by the
total size of MAC service data units (SDUs) served to logical
channel j in step 1. In step 3, if any resources remain, all the
logical channels for which data remains are served in a strict
decreasing priority order until either the data for that logical
channel or the uplink (UL) grant is exhausted, i.e. the MAC PDU is
completely filled.
[0004] A WTRU may be configured with data flows having different
QoS requirements. For example, with guaranteed bit rate (GBR)
bearers, the radio access network (RAN) maintains a guaranteed
bitrate, but data may be transmitted at a higher rate than the GBR.
For a given data radio bearer (DRB), a Maximum Data Burst Volume
(MDBV) is a requirement for 5G network access nodes. MDBV denotes
the largest amount of data that a gNB serves a certain bearer
within a period corresponding to a packet delay budget (PDB) of the
DRB. MDBV ensures that the gNB has a means to control the number of
served DRBs by admission control so that low priority DRBs are not
starved.
[0005] For example, within a packet delay budget of 5 ms, the
network may be configured to admit 20 flows if each flow does not
exceed 320 bytes. However, the network may be configured to only
admit 10 flows if each flow does not exceed 640 bytes. In either
case, statistically, no more than 6400 bytes would be transmitted
over the 5 ms period.
[0006] MDBV requirements are typically enforced by network
implementation for downlink (DL) traffic. This is possible since
the network is in control of both the DL data and the scheduling of
the data. For UL traffic, the network cannot guarantee by
scheduling alone that a bearer will not exceed its MDBV, because
the LCP procedure performed by the WTRU on the UL grant is
performed according to logical channel (LCH) priorities and other
transport block (TB) construction rules. For UL traffic,
enforcement methods are needed to ensure that high priority DRBs do
not negatively impact cell admission capacity or the QoS for other
flows of a similar or lower priority. Additionally, methods for
ensuring that high priority DRBs do not take more than their
expected share of resources are needed.
SUMMARY
[0007] A method performed by a wireless transmit/receive unit
(WTRU) may comprise associating a logical channel with a plurality
of token buckets, including at least a long term token bucket and a
short term token bucket. The method may further comprise
transmitting logical channel data on the associated logical
channel, in a transmission time interval (TTI). The transmitted
logical channel data of the TTI may be no larger than a value
corresponding to a minimum of the long term token bucket and the
short term token bucket. The long term token bucket may be
initialized to a value which is greater than an initialized value
of the short term token bucket. When a WTRU transmits logical
channel data in a TTI, the WTRU may decrement the long term token
bucket and the short term token bucket by a total size of one or
more medium access control (MAC) service data units (SDUs) served
on the associated logical channel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] A more detailed understanding may be had from the following
description, given by way of example in conjunction with the
accompanying drawings, wherein like reference numerals in the
figures indicate like elements, and wherein:
[0009] FIG. 1A is a system diagram illustrating an example
communications system in which one or more disclosed embodiments
may be implemented;
[0010] FIG. 1B is a system diagram illustrating an example wireless
transmit/receive unit (WTRU) that may be used within the
communications system illustrated in FIG. 1A according to an
embodiment;
[0011] FIG. 1C is a system diagram illustrating an example radio
access network (RAN) and an example core network (CN) that may be
used within the communications system illustrated in FIG. 1A
according to an embodiment;
[0012] FIG. 1D is a system diagram illustrating a further example
RAN and a further example CN that may be used within the
communications system illustrated in FIG. 1A according to an
embodiment;
[0013] FIG. 2 is a graph illustrating an example of how the values
of buckets Bj and B'j may evolve with time;
[0014] FIG. 3 is a graph illustrating another two bucket
example;
[0015] FIG. 4A is a flowchart illustrating a first resource
allocation method;
[0016] FIG. 4B is a flowchart illustrating a second resource
allocation method; and
[0017] FIG. 5 is a flowchart illustrating a method for transmitting
data using a long term token bucket and a short term token
bucket.
DETAILED DESCRIPTION
[0018] FIG. 1A is a diagram illustrating an example communications
system 100 in which one or more disclosed embodiments may be
implemented. The communications system 100 may be a multiple access
system that provides content, such as voice, data, video,
messaging, broadcast, etc., to multiple wireless users. The
communications system 100 may enable multiple wireless users to
access such content through the sharing of system resources,
including wireless bandwidth. For example, the communications
systems 100 may employ one or more channel access methods, such as
code division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal FDMA
(OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word
DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM),
resource block-filtered OFDM, filter bank multicarrier (FBMC), and
the like.
[0019] As shown in FIG. 1A, the communications system 100 may
include wireless transmit/receive units (WTRUs) 102a, 102b, 102c,
102d, a RAN 104/113, a CN 106/115, a public switched telephone
network (PSTN) 108, the Internet 110, and other networks 112,
though it will be appreciated that the disclosed embodiments
contemplate any number of WTRUs, base stations, networks, and/or
network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be
any type of device configured to operate and/or communicate in a
wireless environment. By way of example, the WTRUs 102a, 102b,
102c, 102d, any of which may be referred to as a "station" and/or a
"STA", may be configured to transmit and/or receive wireless
signals and may include a user equipment (UE), a mobile station, a
fixed or mobile subscriber unit, a subscription-based unit, a
pager, a cellular telephone, a personal digital assistant (PDA), a
smartphone, a laptop, a netbook, a personal computer, a wireless
sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT)
device, a watch or other wearable, a head-mounted display (HMD), a
vehicle, a drone, a medical device and applications (e.g., remote
surgery), an industrial device and applications (e.g., a robot
and/or other wireless devices operating in an industrial and/or an
automated processing chain contexts), a consumer electronics
device, a device operating on commercial and/or industrial wireless
networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d
may be interchangeably referred to as a UE.
[0020] The communications systems 100 may also include a base
station 114a and/or a base station 114b. Each of the base stations
114a, 114b may be any type of device configured to wirelessly
interface with at least one of the WTRUs 102a, 102b, 102c, 102d to
facilitate access to one or more communication networks, such as
the CN 106/115, the Internet 110, and/or the other networks 112. By
way of example, the base stations 114a, 114b may be a base
transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a
Home eNode B, a gNB, a new radio (NR) NodeB, a site controller, an
access point (AP), a wireless router, and the like. While the base
stations 114a, 114b are each depicted as a single element, it will
be appreciated that the base stations 114a, 114b may include any
number of interconnected base stations and/or network elements.
[0021] The base station 114a may be part of the RAN 104/113, which
may also include other base stations and/or network elements (not
shown), such as a base station controller (BSC), a radio network
controller (RNC), relay nodes, etc. The base station 114a and/or
the base station 114b may be configured to transmit and/or receive
wireless signals on one or more carrier frequencies, which may be
referred to as a cell (not shown). These frequencies may be in
licensed spectrum, unlicensed spectrum, or a combination of
licensed and unlicensed spectrum. A cell may provide coverage for a
wireless service to a specific geographical area that may be
relatively fixed or that may change over time. The cell may further
be divided into cell sectors. For example, the cell associated with
the base station 114a may be divided into three sectors. Thus, in
one embodiment, the base station 114a may include three
transceivers, i.e., one for each sector of the cell. In an
embodiment, the base station 114a may employ multiple-input
multiple output (MIMO) technology and may utilize multiple
transceivers for each sector of the cell. For example, beamforming
may be used to transmit and/or receive signals in desired spatial
directions.
[0022] The base stations 114a, 114b may communicate with one or
more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116,
which may be any suitable wireless communication link (e.g., radio
frequency (RF), microwave, centimeter wave, micrometer wave,
infrared (IR), ultraviolet (UV), visible light, etc.). The air
interface 116 may be established using any suitable radio access
technology (RAT).
[0023] More specifically, as noted above, the communications system
100 may be a multiple access system and may employ one or more
channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA,
and the like. For example, the base station 114a in the RAN 104/113
and the WTRUs 102a, 102b, 102c may implement a radio technology
such as Universal Mobile Telecommunications System (UMTS)
Terrestrial Radio Access (UTRA), which may establish the air
interface 115/116/117 using wideband CDMA (WCDMA). WCDMA may
include communication protocols such as High-Speed Packet Access
(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed
Downlink (DL) Packet Access (HSDPA) and/or High-Speed Uplink Packet
Access (HSUPA).
[0024] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement a radio technology such as Evolved UMTS
Terrestrial Radio Access (E-UTRA), which may establish the air
interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced
(LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).
[0025] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement a radio technology such as NR Radio
Access, which may establish the air interface 116 using New Radio
(NR).
[0026] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c may implement multiple radio access technologies. For
example, the base station 114a and the WTRUs 102a, 102b, 102c may
implement LTE radio access and NR radio access together, for
instance using dual connectivity (DC) principles. Thus, the air
interface utilized by WTRUs 102a, 102b, 102c may be characterized
by multiple types of radio access technologies and/or transmissions
sent to/from multiple types of base stations (e.g., a eNB and a
gNB).
[0027] In other embodiments, the base station 114a and the WTRUs
102a, 102b, 102c may implement radio technologies such as IEEE
802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e.,
Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,
CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000),
Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global
System for Mobile communications (GSM), Enhanced Data rates for GSM
Evolution (EDGE), GSM EDGE (GERAN), and the like.
[0028] The base station 114b in FIG. 1A may be a wireless router,
Home Node B, Home eNode B, or access point, for example, and may
utilize any suitable RAT for facilitating wireless connectivity in
a localized area, such as a place of business, a home, a vehicle, a
campus, an industrial facility, an air corridor (e.g., for use by
drones), a roadway, and the like. In one embodiment, the base
station 114b and the WTRUs 102c, 102d may implement a radio
technology such as IEEE 802.11 to establish a wireless local area
network (WLAN). In an embodiment, the base station 114b and the
WTRUs 102c, 102d may implement a radio technology such as IEEE
802.15 to establish a wireless personal area network (WPAN). In yet
another embodiment, the base station 114b and the WTRUs 102c, 102d
may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,
LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As
shown in FIG. 1A, the base station 114b may have a direct
connection to the Internet 110. Thus, the base station 114b may not
be required to access the Internet 110 via the CN 106/115.
[0029] The RAN 104/113 may be in communication with the CN 106/115,
which may be any type of network configured to provide voice, data,
applications, and/or voice over internet protocol (VoIP) services
to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may
have varying quality of service (QoS) requirements, such as
differing throughput requirements, latency requirements, error
tolerance requirements, reliability requirements, data throughput
requirements, mobility requirements, and the like. The CN 106/115
may provide call control, billing services, mobile location-based
services, pre-paid calling, Internet connectivity, video
distribution, etc., and/or perform high-level security functions,
such as user authentication. Although not shown in FIG. 1A, it will
be appreciated that the RAN 104/113 and/or the CN 106/115 may be in
direct or indirect communication with other RANs that employ the
same RAT as the RAN 104/113 or a different RAT. For example, in
addition to being connected to the RAN 104/113, which may be
utilizing a NR radio technology, the CN 106/115 may also be in
communication with another RAN (not shown) employing a GSM, UMTS,
CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.
[0030] The CN 106/115 may also serve as a gateway for the WTRUs
102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110,
and/or the other networks 112. The PSTN 108 may include
circuit-switched telephone networks that provide plain old
telephone service (POTS). The Internet 110 may include a global
system of interconnected computer networks and devices that use
common communication protocols, such as the transmission control
protocol (TCP), user datagram protocol (UDP) and/or the internet
protocol (IP) in the TCP/IP internet protocol suite. The networks
112 may include wired and/or wireless communications networks owned
and/or operated by other service providers. For example, the
networks 112 may include another CN connected to one or more RANs,
which may employ the same RAT as the RAN 104/113 or a different
RAT.
[0031] Some or all of the WTRUs 102a, 102b, 102c, 102d in the
communications system 100 may include multi-mode capabilities
(e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple
transceivers for communicating with different wireless networks
over different wireless links). For example, the WTRU 102c shown in
FIG. 1A may be configured to communicate with the base station
114a, which may employ a cellular-based radio technology, and with
the base station 114b, which may employ an IEEE 802 radio
technology.
[0032] FIG. 1B is a system diagram illustrating an example WTRU
102. As shown in FIG. 1B, the WTRU 102 may include a processor 118,
a transceiver 120, a transmit/receive element 122, a
speaker/microphone 124, a keypad 126, a display/touchpad 128,
non-removable memory 130, removable memory 132, a power source 134,
a global positioning system (GPS) chipset 136, and/or other
peripherals 138, among others. It will be appreciated that the WTRU
102 may include any sub-combination of the foregoing elements while
remaining consistent with an embodiment.
[0033] The processor 118 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Arrays (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 118 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the WTRU 102 to operate in a wireless environment. The
processor 118 may be coupled to the transceiver 120, which may be
coupled to the transmit/receive element 122. While FIG. 1B depicts
the processor 118 and the transceiver 120 as separate components,
it will be appreciated that the processor 118 and the transceiver
120 may be integrated together in an electronic package or
chip.
[0034] The transmit/receive element 122 may be configured to
transmit signals to, or receive signals from, a base station (e.g.,
the base station 114a) over the air interface 116. For example, in
one embodiment, the transmit/receive element 122 may be an antenna
configured to transmit and/or receive RF signals. In an embodiment,
the transmit/receive element 122 may be an emitter/detector
configured to transmit and/or receive IR, UV, or visible light
signals, for example. In yet another embodiment, the
transmit/receive element 122 may be configured to transmit and/or
receive both RF and light signals. It will be appreciated that the
transmit/receive element 122 may be configured to transmit and/or
receive any combination of wireless signals.
[0035] Although the transmit/receive element 122 is depicted in
FIG. 1B as a single element, the WTRU 102 may include any number of
transmit/receive elements 122. More specifically, the WTRU 102 may
employ MIMO technology. Thus, in one embodiment, the WTRU 102 may
include two or more transmit/receive elements 122 (e.g., multiple
antennas) for transmitting and receiving wireless signals over the
air interface 116.
[0036] The transceiver 120 may be configured to modulate the
signals that are to be transmitted by the transmit/receive element
122 and to demodulate the signals that are received by the
transmit/receive element 122. As noted above, the WTRU 102 may have
multi-mode capabilities. Thus, the transceiver 120 may include
multiple transceivers for enabling the WTRU 102 to communicate via
multiple RATs, such as NR and IEEE 802.11, for example.
[0037] The processor 118 of the WTRU 102 may be coupled to, and may
receive user input data from, the speaker/microphone 124, the
keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal
display (LCD) display unit or organic light-emitting diode (OLED)
display unit). The processor 118 may also output user data to the
speaker/microphone 124, the keypad 126, and/or the display/touchpad
128. In addition, the processor 118 may access information from,
and store data in, any type of suitable memory, such as the
non-removable memory 130 and/or the removable memory 132. The
non-removable memory 130 may include random-access memory (RAM),
read-only memory (ROM), a hard disk, or any other type of memory
storage device. The removable memory 132 may include a subscriber
identity module (SIM) card, a memory stick, a secure digital (SD)
memory card, and the like. In other embodiments, the processor 118
may access information from, and store data in, memory that is not
physically located on the WTRU 102, such as on a server or a home
computer (not shown).
[0038] The processor 118 may receive power from the power source
134, and may be configured to distribute and/or control the power
to the other components in the WTRU 102. The power source 134 may
be any suitable device for powering the WTRU 102. For example, the
power source 134 may include one or more dry cell batteries (e.g.,
nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride
(NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and
the like.
[0039] The processor 118 may also be coupled to the GPS chipset
136, which may be configured to provide location information (e.g.,
longitude and latitude) regarding the current location of the WTRU
102. In addition to, or in lieu of, the information from the GPS
chipset 136, the WTRU 102 may receive location information over the
air interface 116 from a base station (e.g., base stations 114a,
114b) and/or determine its location based on the timing of the
signals being received from two or more nearby base stations. It
will be appreciated that the WTRU 102 may acquire location
information by way of any suitable location-determination method
while remaining consistent with an embodiment.
[0040] The processor 118 may further be coupled to other
peripherals 138, which may include one or more software and/or
hardware modules that provide additional features, functionality
and/or wired or wireless connectivity. For example, the peripherals
138 may include an accelerometer, an e-compass, a satellite
transceiver, a digital camera (for photographs and/or video), a
universal serial bus (USB) port, a vibration device, a television
transceiver, a hands free headset, a Bluetooth.RTM. module, a
frequency modulated (FM) radio unit, a digital music player, a
media player, a video game player module, an Internet browser, a
Virtual Reality and/or Augmented Reality (VR/AR) device, an
activity tracker, and the like. The peripherals 138 may include one
or more sensors, the sensors may be one or more of a gyroscope, an
accelerometer, a hall effect sensor, a magnetometer, an orientation
sensor, a proximity sensor, a temperature sensor, a time sensor; a
geolocation sensor; an altimeter, a light sensor, a touch sensor, a
magnetometer, a barometer, a gesture sensor, a biometric sensor,
and/or a humidity sensor.
[0041] The WTRU 102 may include a full duplex radio for which
transmission and reception of some or all of the signals (e.g.,
associated with particular subframes for both the uplink (UL)
(e.g., for transmission) and downlink (e.g., for reception) may be
concurrent and/or simultaneous. The full duplex radio may include
an interference management unit 139 to reduce and or substantially
eliminate self-interference via either hardware (e.g., a choke) or
signal processing via a processor (e.g., a separate processor (not
shown) or via processor 118). In an embodiment, the WRTU 102 may
include a half-duplex radio for which transmission and reception of
some or all of the signals (e.g., associated with particular
subframes for either the UL (e.g., for transmission) or the
downlink (e.g., for reception)).
[0042] FIG. 10 is a system diagram illustrating the RAN 104 and the
CN 106 according to an embodiment. As noted above, the RAN 104 may
employ an E-UTRA radio technology to communicate with the WTRUs
102a, 102b, 102c over the air interface 116. The RAN 104 may also
be in communication with the CN 106.
[0043] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it
will be appreciated that the RAN 104 may include any number of
eNode-Bs while remaining consistent with an embodiment. The
eNode-Bs 160a, 160b, 160c may each include one or more transceivers
for communicating with the WTRUs 102a, 102b, 102c over the air
interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may
implement MIMO technology. Thus, the eNode-B 160a, for example, may
use multiple antennas to transmit wireless signals to, and/or
receive wireless signals from, the WTRU 102a.
[0044] Each of the eNode-Bs 160a, 160b, 160c may be associated with
a particular cell (not shown) and may be configured to handle radio
resource management decisions, handover decisions, scheduling of
users in the UL and/or DL, and the like. As shown in FIG. 10, the
eNode-Bs 160a, 160b, 160c may communicate with one another over an
X2 interface.
[0045] The CN 106 shown in FIG. 10 may include a mobility
management entity (MME) 162, a serving gateway (SGW) 164, and a
packet data network (PDN) gateway (or PGW) 166. While each of the
foregoing elements are depicted as part of the CN 106, it will be
appreciated that any of these elements may be owned and/or operated
by an entity other than the CN operator.
[0046] The MME 162 may be connected to each of the eNode-Bs 162a,
162b, 162c in the RAN 104 via an S1 interface and may serve as a
control node. For example, the MME 162 may be responsible for
authenticating users of the WTRUs 102a, 102b, 102c, bearer
activation/deactivation, selecting a particular serving gateway
during an initial attach of the WTRUs 102a, 102b, 102c, and the
like. The MME 162 may provide a control plane function for
switching between the RAN 104 and other RANs (not shown) that
employ other radio technologies, such as GSM and/or WCDMA.
[0047] The SGW 164 may be connected to each of the eNode Bs 160a,
160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may
generally route and forward user data packets to/from the WTRUs
102a, 102b, 102c. The SGW 164 may perform other functions, such as
anchoring user planes during inter-eNode B handovers, triggering
paging when DL data is available for the WTRUs 102a, 102b, 102c,
managing and storing contexts of the WTRUs 102a, 102b, 102c, and
the like.
[0048] The SGW 164 may be connected to the PGW 166, which may
provide the WTRUs 102a, 102b, 102c with access to packet-switched
networks, such as the Internet 110, to facilitate communications
between the WTRUs 102a, 102b, 102c and IP-enabled devices.
[0049] The CN 106 may facilitate communications with other
networks. For example, the CN 106 may provide the WTRUs 102a, 102b,
102c with access to circuit-switched networks, such as the PSTN
108, to facilitate communications between the WTRUs 102a, 102b,
102c and traditional land-line communications devices. For example,
the CN 106 may include, or may communicate with, an internet
protocol (IP) gateway (e.g., an IP multimedia subsystem (IMS)
server) that serves as an interface between the CN 106 and the PSTN
108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c
with access to the other networks 112, which may include other
wired and/or wireless networks that are owned and/or operated by
other service providers.
[0050] Although the WTRU is described in FIGS. 1A-1D as a wireless
terminal, it is contemplated that in certain representative
embodiments that such a terminal may use (e.g., temporarily or
permanently) wired communication interfaces with the communication
network.
[0051] In representative embodiments, the other network 112 may be
a WLAN.
[0052] A WLAN in Infrastructure Basic Service Set (BSS) mode may
have an Access Point (AP) for the BSS and one or more stations
(STAs) associated with the AP. The AP may have an access or an
interface to a Distribution System (DS) or another type of
wired/wireless network that carries traffic in to and/or out of the
BSS. Traffic to STAs that originates from outside the BSS may
arrive through the AP and may be delivered to the STAs. Traffic
originating from STAs to destinations outside the BSS may be sent
to the AP to be delivered to respective destinations. Traffic
between STAs within the BSS may be sent through the AP, for
example, where the source STA may send traffic to the AP and the AP
may deliver the traffic to the destination STA. The traffic between
STAs within a BSS may be considered and/or referred to as
peer-to-peer traffic. The peer-to-peer traffic may be sent between
(e.g., directly between) the source and destination STAs with a
direct link setup (DLS). In certain representative embodiments, the
DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A
WLAN using an Independent BSS (IBSS) mode may not have an AP, and
the STAs (e.g., all of the STAs) within or using the IBSS may
communicate directly with each other. The IBSS mode of
communication may sometimes be referred to herein as an "ad-hoc"
mode of communication.
[0053] When using the 802.11ac infrastructure mode of operation or
a similar mode of operations, the AP may transmit a beacon on a
fixed channel, such as a primary channel. The primary channel may
be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set
width via signaling. The primary channel may be the operating
channel of the BSS and may be used by the STAs to establish a
connection with the AP. In certain representative embodiments,
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
may be implemented, for example in in 802.11 systems. For CSMA/CA,
the STAs (e.g., every STA), including the AP, may sense the primary
channel. If the primary channel is sensed/detected and/or
determined to be busy by a particular STA, the particular STA may
back off. One STA (e.g., only one station) may transmit at any
given time in a given BSS.
[0054] High Throughput (HT) STAs may use a 40 MHz wide channel for
communication, for example, via a combination of the primary 20 MHz
channel with an adjacent or nonadjacent 20 MHz channel to form a 40
MHz wide channel.
[0055] Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz,
80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz,
channels may be formed by combining contiguous 20 MHz channels. A
160 MHz channel may be formed by combining 8 contiguous 20 MHz
channels, or by combining two non-contiguous 80 MHz channels, which
may be referred to as an 80+80 configuration. For the 80+80
configuration, the data, after channel encoding, may be passed
through a segment parser that may divide the data into two streams.
Inverse Fast Fourier Transform (IFFT) processing, and time domain
processing, may be done on each stream separately. The streams may
be mapped on to the two 80 MHz channels, and the data may be
transmitted by a transmitting STA. At the receiver of the receiving
STA, the above described operation for the 80+80 configuration may
be reversed, and the combined data may be sent to the Medium Access
Control (MAC).
[0056] Sub 1 GHz modes of operation are supported by 802.11af and
802.11ah. The channel operating bandwidths, and carriers, are
reduced in 802.11af and 802.11ah relative to those used in 802.11n,
and 802.11ac. 802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths
in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz,
2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum.
According to a representative embodiment, 802.11ah may support
Meter Type Control/Machine-Type Communications, such as
machine-type communications (MTC) devices in a macro coverage area.
MTC devices may have certain capabilities, for example, limited
capabilities including support for (e.g., only support for) certain
and/or limited bandwidths. The MTC devices may include a battery
with a battery life above a threshold (e.g., to maintain a very
long battery life).
[0057] WLAN systems, which may support multiple channels, and
channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and
802.11ah, include a channel which may be designated as the primary
channel. The primary channel may have a bandwidth equal to the
largest common operating bandwidth supported by all STAs in the
BSS. The bandwidth of the primary channel may be set and/or limited
by a STA, from among all STAs in operating in a BSS, which supports
the smallest bandwidth operating mode. In the example of 802.11ah,
the primary channel may be 1 MHz wide for STAs (e.g., MTC type
devices) that support (e.g., only support) a 1 MHz mode, even if
the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16
MHz, and/or other channel bandwidth operating modes. Carrier
sensing and/or Network Allocation Vector (NAV) settings may depend
on the status of the primary channel. If the primary channel is
busy, for example, due to a STA (which supports only a 1 MHz
operating mode), transmitting to the AP, the entire available
frequency bands may be considered busy even though a majority of
the frequency bands remains idle and may be available.
[0058] In the United States, the available frequency bands, which
may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the
available frequency bands are from 917.5 MHz to 923.5 MHz. In
Japan, the available frequency bands are from 916.5 MHz to 927.5
MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz
depending on the country code.
[0059] FIG. 1D is a system diagram illustrating the RAN 113 and the
CN 115 according to an embodiment. As noted above, the RAN 113 may
employ an NR radio technology to communicate with the WTRUs 102a,
102b, 102c over the air interface 116. The RAN 113 may also be in
communication with the CN 115.
[0060] The RAN 113 may include gNBs 180a, 180b, 180c, though it
will be appreciated that the RAN 113 may include any number of gNBs
while remaining consistent with an embodiment. The gNBs 180a, 180b,
180c may each include one or more transceivers for communicating
with the WTRUs 102a, 102b, 102c over the air interface 116. In one
embodiment, the gNBs 180a, 180b, 180c may implement MIMO
technology. For example, gNBs 180a, 108b may utilize beamforming to
transmit signals to and/or receive signals from the gNBs 180a,
180b, 180c. Thus, the gNB 180a, for example, may use multiple
antennas to transmit wireless signals to, and/or receive wireless
signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b,
180c may implement carrier aggregation technology. For example, the
gNB 180a may transmit multiple component carriers to the WTRU 102a
(not shown). A subset of these component carriers may be on
unlicensed spectrum while the remaining component carriers may be
on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c
may implement Coordinated Multi-Point (CoMP) technology. For
example, WTRU 102a may receive coordinated transmissions from gNB
180a and gNB 180b (and/or gNB 180c).
[0061] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a,
180b, 180c using transmissions associated with a scalable
numerology. For example, the OFDM symbol spacing and/or OFDM
subcarrier spacing may vary for different transmissions, different
cells, and/or different portions of the wireless transmission
spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs
180a, 180b, 180c using subframe or transmission time intervals
(TTIs) of various or scalable lengths (e.g., containing varying
number of OFDM symbols and/or lasting varying lengths of absolute
time).
[0062] The gNBs 180a, 180b, 180c may be configured to communicate
with the WTRUs 102a, 102b, 102c in a standalone configuration
and/or a non-standalone configuration. In the standalone
configuration, WTRUs 102a, 102b, 102c may communicate with gNBs
180a, 180b, 180c without also accessing other RANs (e.g., such as
eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs
102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c
as a mobility anchor point. In the standalone configuration, WTRUs
102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using
signals in an unlicensed band. In a non-standalone configuration
WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a,
180b, 180c while also communicating with/connecting to another RAN
such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b,
102c may implement DC principles to communicate with one or more
gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c
substantially simultaneously. In the non-standalone configuration,
eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs
102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional
coverage and/or throughput for servicing WTRUs 102a, 102b,
102c.
[0063] Each of the gNBs 180a, 180b, 180c may be associated with a
particular cell (not shown) and may be configured to handle radio
resource management decisions, handover decisions, scheduling of
users in the UL and/or DL, support of network slicing, dual
connectivity, interworking between NR and E-UTRA, routing of user
plane data towards User Plane Function (UPF) 184a, 184b, routing of
control plane information towards Access and Mobility Management
Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the
gNBs 180a, 180b, 180c may communicate with one another over an Xn
interface.
[0064] The CN 115 shown in FIG. 1D may include at least one AMF
182a, 182b, at least one UPF 184a, 184b, at least one Session
Management Function (SMF) 183a, 183b, and possibly a Data Network
(DN) 185a, 185b. While each of the foregoing elements are depicted
as part of the CN 115, it will be appreciated that any of these
elements may be owned and/or operated by an entity other than the
CN operator.
[0065] The AMF 182a, 182b may be connected to one or more of the
gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may
serve as a control node. For example, the AMF 182a, 182b may be
responsible for authenticating users of the WTRUs 102a, 102b, 102c,
support for network slicing (e.g., handling of different protocol
data unit (PDU) sessions with different requirements), selecting a
particular SMF 183a, 183b, management of the registration area,
termination of non-access stratum (NAS) signaling, mobility
management, and the like. Network slicing may be used by the AMF
182a, 182b in order to customize CN support for WTRUs 102a, 102b,
102c based on the types of services being utilized WTRUs 102a,
102b, 102c. For example, different network slices may be
established for different use cases such as services relying on
ultra-reliable low latency (URLLC) access, services relying on
enhanced massive mobile broadband (eMBB) access, services for
machine type communication (MTC) access, and/or the like. The AMF
162 may provide a control plane function for switching between the
RAN 113 and other RANs (not shown) that employ other radio
technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access
technologies such as WiFi.
[0066] The SMF 183a, 183b may be connected to an AMF 182a, 182b in
the CN 115 via an N11 interface. The SMF 183a, 183b may also be
connected to a UPF 184a, 184b in the CN 115 via an N4 interface.
The SMF 183a, 183b may select and control the UPF 184a, 184b and
configure the routing of traffic through the UPF 184a, 184b. The
SMF 183a, 183b may perform other functions, such as managing and
allocating UE IP address, managing PDU sessions, controlling policy
enforcement and QoS, providing downlink data notifications, and the
like. A PDU session type may be IP-based, non-IP based,
Ethernet-based, and the like.
[0067] The UPF 184a, 184b may be connected to one or more of the
gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may
provide the WTRUs 102a, 102b, 102c with access to packet-switched
networks, such as the Internet 110, to facilitate communications
between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF
184, 184b may perform other functions, such as routing and
forwarding packets, enforcing user plane policies, supporting
multi-homed PDU sessions, handling user plane QoS, buffering
downlink packets, providing mobility anchoring, and the like.
[0068] The CN 115 may facilitate communications with other
networks. For example, the CN 115 may include, or may communicate
with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server)
that serves as an interface between the CN 115 and the PSTN 108. In
addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with
access to the other networks 112, which may include other wired
and/or wireless networks that are owned and/or operated by other
service providers. In one embodiment, the WTRUs 102a, 102b, 102c
may be connected to a local Data Network (DN) 185a, 185b through
the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and
an N6 interface between the UPF 184a, 184b and the DN 185a,
185b.
[0069] In view of FIGS. 1A-1D, and the corresponding description of
FIGS. 1A-1D, one or more, or all, of the functions described herein
with regard to one or more of: WTRU 102a-d, Base Station 114a-b,
eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab,
UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s)
described herein, may be performed by one or more emulation devices
(not shown). The emulation devices may be one or more devices
configured to emulate one or more, or all, of the functions
described herein. For example, the emulation devices may be used to
test other devices and/or to simulate network and/or WTRU
functions.
[0070] The emulation devices may be designed to implement one or
more tests of other devices in a lab environment and/or in an
operator network environment. For example, the one or more
emulation devices may perform the one or more, or all, functions
while being fully or partially implemented and/or deployed as part
of a wired and/or wireless communication network in order to test
other devices within the communication network. The one or more
emulation devices may perform the one or more, or all, functions
while being temporarily implemented/deployed as part of a wired
and/or wireless communication network. The emulation device may be
directly coupled to another device for purposes of testing and/or
may performing testing using over-the-air wireless
communications.
[0071] The one or more emulation devices may perform the one or
more, including all, functions while not being implemented/deployed
as part of a wired and/or wireless communication network. For
example, the emulation devices may be utilized in a testing
scenario in a testing laboratory and/or a non-deployed (e.g.,
testing) wired and/or wireless communication network in order to
implement testing of one or more components. The one or more
emulation devices may be test equipment. Direct RF coupling and/or
wireless communications via RF circuitry (e.g., which may include
one or more antennas) may be used by the emulation devices to
transmit and/or receive data.
[0072] Mobile communication technologies are in continuous
evolution and are already at the doorstep of a fifth cellular
incarnation--5G. As with previous generations, new use cases will
largely contribute to setting the requirements for new systems. The
5G New Radio (NR) access network may enable improved broadband
performance (IBB); industrial control and communications (ICC) and
vehicular applications (V2X); and Massive Machine-Type
Communications (mMTC) use cases. Such use cases may be enabled
through one or more of the following example requirements for the
5G interface.
[0073] Support for ultra-low transmission latency communication
technologies, for example, low latency communications (LLC) may
enable various use cases. For example, an air interface latency as
low as 1 ms round-trip time (RTT) may require support for TTIs
somewhere between 100 us and 250 us. Support for ultra-low access
latency including a time from initial system access until the
completion of the transmission of the first user plane data unit is
of interest, but is of lesser priority. IC and V2X may require an
end-to-end (e2e) latency of less than 10 ms. Support for
ultra-reliable transmission (URC) may enable various use cases. One
example design consideration may include providing a transmission
reliability that is much better than what is possible with legacy
LTE systems. For example, a possible target may be close to 99.999%
transmission success and service availability. Another example
design consideration may include providing support for mobility for
speed in the range of 0-500 km/h. IC and V2X may require a Packet
Loss Ratio of less than 10e.sup.-6. Support for MTC operation
(including narrowband operation) may enable various use cases. In
one example, the air interface efficiently supports narrowband
operation (e.g., using less than 200 KHz), extended battery life
(e.g., up to 15 years of autonomy) and minimal communication
overhead for small and infrequent data transmissions (e.g., low
data rate in the range of 1-100 kbps) with an access latency of
seconds to hours.
[0074] 5G may further support legacy LTE Radio Access in addition
to the NR access. For example, a WTRU may be configured for dual
connectivity with LTE cells configured as a master cell group (MCG)
and NR cells configured as a secondary cell group (SCG) in an
E-UTRAN New Radio-Dual Connectivity (EN-DC) configuration. Various
methods, systems, and devices are described herein without
limitation to other use cases and/or technologies, e.g., those
applicable to LTE and/or NR-based systems.
[0075] Various general principles behind LTE and NR include, for
example, channel and physical layer resources, bandwidth parts
(BWPs), spectrum and carrier aggregation (CA), supplementary uplink
(SUL), transport block (TB) for uplink (UL) transmissions, logical
channels (LCHs), logical channel grouping (LCG), logical channel
prioritization (LCP) for UL transmissions, transport channels
(TRCHs), and QoS-based parameters. Each of these general principles
may be enhanced or modified in accordance with embodiments
disclosed herein.
[0076] LTE and NR communications may employ various channel and
physical layer resources. For example, in NR, a WTRU may be
configured with downlink control channel resources for each cell of
a configuration of a WTRU, such as one or more search space
configurations or one or more CORESET configurations for each cell
of the configured WTRU. The WTRU may be configured with uplink
control channel resources for each cell of the WTRU's configuration
such as one or more physical uplink control channel (PUCCH)
configurations for each cell of the WTRU's configuration. The WTRU
may be configured with physical random access channel resources for
each cell of the WTRU's configuration such as one or more physical
random access channel (PRACH) configurations for each cell of the
WTRU's configuration. The WTRU may use such resources to perform a
random access procedure and/or for beamforming management such as
for establishment of beams and/or recovery from a beam failure
event.
[0077] LTE and NR communications may employ bandwidth parts (BWPs)
so that resources may be assigned in a flexible manner in a given
carrier. For example, a WTRU may be configured with one or more
bandwidth part(s) (BWP) for a given cell and/or carrier. A BWP may
be characterized by at least one of a subcarrier spacing; a cyclic
prefix; and/or a number of contiguous PRBs. These characteristics
may be referred to as configuration aspects of the WTRU. Further, a
BWP may be further characterized by a frequency location (e.g., a
center frequency.)
[0078] A WTRU may be configured with an initial BWP. For example,
the WTRU may be configured with an initial BWP from the reception
of system information via a SIB. The WTRU may be configured to
access the system using the initial BWP for a given cell and/or
carrier. Such access may include at an initial access time when the
WTRU is in an IDLE mode and/or determines that it should establish
a radio resource control (RRC) connection to the system. The
configuration of such initial BWP may include a configuration for
random access.
[0079] A WTRU, for example, a CONNECTED mode WTRU may be further
configured with a default BWP. The default BWP may be the same or
similar to the initial BWP, or it may be different. The WTRU may
revert to the default BWP at the expiration of a timer, for
example, after a period of scheduling inactivity. A WTRU may be
configured with additional BWPs. For example, the WTRU may be
configured with a BWP for a specific type of data transfers, for
example, for URLLC transmissions, eMTC transmissions or eMBB
transmissions.
[0080] LTE and NR communications may employ one or both of spectrum
aggregation and carrier aggregation (CA). For single carrier
operation, spectrum aggregation may be supported, whereby the WTRU
may support transmission and reception of multiple transport blocks
over contiguous or non-contiguous sets physical resource blocks
(PRBs) within the same operating band. Mapping of a single
transport block to one or more separate sets of PRBs may also be
supported. Support for simultaneous transmissions associated to
different waveforms, transmission durations, sub-carrier spacing
(SCS) requirements may also be supported.
[0081] Multicarrier operation may also be supported using
contiguous or non-contiguous spectrum blocks within the same
operating band or across two or more operating bands. Aggregation
of spectrum blocks using different modes, for example, frequency
division duplex (FDD) and time division duplex (TDD) modes may be
supported. Each of these modes may be configured using different
channel access methods, for example, licensed and/or unlicensed
band operation above or below 6 GHz, may be supported. Support for
methods that configure, reconfigure and/or dynamically change the
WTRU's multicarrier aggregation may be supported. The WTRU may be
configured for carrier aggregation using a single MAC instance, or
for multi-connectivity operation with one MAC instance per
configured group of cells. A WTRU configured for dual connectivity
operation may be configured with one or more cells for the MCG, and
one or more cells for the SCG.
[0082] A WTRU may be configured with one or more cells including,
for example, a Primary Cell (PCell) and zero or more Secondary
Cells (SCells). The WTRU may be configured with one or more groups
of cells denoted by a Cell Group (CG). The WTRU may be configured
with one special cell (SpCell) or Primary Special Cell (PSCell) for
a CG. The primary CG or MCG may always include at least one PCell.
The WTRU may be configured for carrier aggregation, in which case,
at least one PCell may be configured for a CG. The WTRU may be
configured with multiple CGs for operation using dual
connectivity.
[0083] LTE and NR communications may employ supplementary uplink
(SUL) access via one or more SUL carriers. For example, a cell of
the WTRU's configuration may include at least one additional uplink
carrier. In NR, the WTRU may be configured with a cell including a
SUL cell. One motivation for the use of an SUL may be to extend the
coverage of a WTRU operating in high frequency, such that the WTRU
may perform transmissions on the SUL when configured to a lower
frequency band. This may be useful when the WTRU moves towards the
edge of the coverage of the cell's primary uplink carrier (PUL).
Another use of the SUL may be for provision of specific services,
higher throughput and/or increased reliability. This may be
preferable if the WTRU is configured to perform transmissions on
multiple uplinks for the concerned cells concurrently or near
concurrently in a time division multiplexed (TDM) fashion.
[0084] For example, the SUL may be modeled in NR as a cell with a
DL carrier associated with two separate UL carriers. The uplink
carrier may consist or may be comprised of of a primary UL, which
may be in the high frequency band where the DL carrier is also
located, and an SUL which may be in a lower frequency band. The
terms PUL and SUL are used herein to refer to the regular uplink
and supplementary uplink. SUL may be configured for any type of
cell, including but is not limited to a primary cell (PCell), a
secondary cell (SCell) as well as a secondary PCell (SPCell) for
dual connectivity. The SUL may be configured for a standalone
system, or for a cell of a multi-RAT dual connectivity system. The
WTRU may perform initial access to a cell using either PUL or SUL.
The SUL's configuration may be broadcasted in minimum SI for a
cell. For example, the WTRU may select the SUL for initial access
if the DL quality of the serving cell is below a configured
threshold.
[0085] Different operating modes may be configured for SUL for a
WTRU in RRC Connected mode. For example, in a first mode, RRC may
configure the WTRU with multiple UL carriers, one of which is a PUL
with a typical uplink configuration for the concerned cell, and
another which may minimally include a sounding reference signal
(SRS) configuration on the SUL or another carrier or cell. In such
a mode of operation, the WTRU may use the PUL for all control and
data transmission in the uplink. The WTRU may additionally transmit
SRS using resources of the SUL. The RRC reconfiguration may provide
an extended, typical and/or complete uplink configuration for a
different carrier to activate and/or switch the applicable active
uplink carrier for the cell for some or all transmissions.
[0086] In a second example mode, RRC may configure multiple uplinks
with an extended, typical and/or complete, uplink configuration. In
such case, the WTRU may have a configuration sufficient to perform
some or all types of uplink transmissions, for example, PUCCH,
physical uplink shared channel (PUSCH) and/or PRACH transmissions
on resources of the concerned carriers. The WTRU may subsequently
receive control signaling via, for example, a MAC CE or DCI that
activates and/or initiates a switch between the UL
configurations.
[0087] In a third example mode, multiple uplinks may be configured
by RRC, and two or more uplink configurations may be active either
concurrently or in a time-division fashion. Such mode of operation
may include a restriction such that the WTRU may not be required to
perform some or all types of uplink transmissions simultaneously.
In this way, the WTRU may not be required to transmit PUSCH for the
cell simultaneously on multiple uplink carriers. In some cases,
such restriction may be configured for the WTRU in particular if a
capability of the indicates that such simultaneous transmission is
not supported, for example, for the configured frequency bands. A
WTRU capability may be provided to a base station, gNB, core
network or the like via a single capability identifier or a
capability identifier which is indicative of a plurality of
capabilities of the WTRU.
[0088] LTE and NR communications may employ transport blocks (TBs)
for UL transmissions. In LTE and in NR, the NW may grant radio
resources to the WTRU for a transmission on the UL shared channel
(UL-SCH). The WTRU may receive such resource allocations either in
one or more grants received on the Physical Downlink Control
Channel (PDCCH) or in a configured resource, for example, a
semi-persistently scheduled UL grant in LTE, or a type-1 grant or a
type-2 grant in NR. The medium access control (MAC) layer may
provide the Hybrid Automatic Repeat Request (HARQ) entity with the
necessary information for the UL transmission. This information may
include one or more of a New Data Indication (NDI) which controls
whether or not the uplink transmission should be a new transmission
or a retransmission; a transmission unit, for example, a transport
block (TB) size indicating a number of bits, symbols or elements
available for the uplink transmission; a redundancy version (RV);
and/or a transmission duration, for example, a transmission time
interval TTI, number of slots, number of symbols, time period or
the like. Typically, in a single carrier system, there is at most a
single TB of a given transmission duration at any given time.
[0089] A HARQ entity typically identifies the HARQ process for
which the transmission should take place. The HARQ entity may also
route HARQ feedback and a Modulation and Coding Scheme (MCS) to the
HARQ process. The values of the NDI, TB size, RV TTI, and MCS may
be controlled by the NW and may be selected to meet Quality of
Service (QoS) requirements, such as the Packet Delay Budget (PDB),
the Packet Error Loss Rate (PLER) and corresponding radio Block
Error Rate (BLER) target of the different radio bearers established
for the WTRU, based on, for example, Buffer Status Reporting (BSR)
information, reported Channel Quality Indications (CQI) and/or HARQ
feedback received from the WTRU.
[0090] To assemble the MAC Protocol Data Unit (PDU) for
transmission, the WTRU may multiplex one or more MAC Service Data
Unit(s) (SDUs) from one or different logical channels (LCHs) onto
the TB to be delivered to the physical layer on the proper
transport channel. Such multiplexing may include considerations for
mapping restrictions between data from an LCH and a given TB based
on one or more characteristics of the transmission of the TB. Such
characteristics may include the SCS, the maximum PUSCH transmission
duration, measured in terms of a number of TTIs, symbols or the
like, the type of configured grant (e.g., type 1, type 2) and/or
the serving cell(s) allowed for transmission of the data for an
LCH.
[0091] LTE and NR communications may employ logical channels
(LCHs). An LCH may represent a logical association between data
packets and/or PDUs. Such associations may be based on data units,
for example, data packets being associated to the same bearer
similar to legacy methods employed in LTE.
[0092] A WTRU may be configured such that it may determine such
relationships between different data units. Such relationships may
be based on a matching function, for example, based on the
configuration of one or more field values common to data units that
are part of the same logical association. Such fields may
correspond to fields in a protocol header associated with the data
unit(s). For example, such matching functions may use a tuple of
parameters for fields of the IP headers of the data unit, such as
IP source/destination address(es), transport protocol
source/destination port(s), transport protocol type, and/or IP
protocol version, for example, IPv4 or IPv6.) Data units that are
part of the same logical association may share a common radio
bearer and/or may at least conceptually correspond to the same LCH
and/or LCG.
[0093] In NR, the WTRU may be configured with a service data
adaptation protocol (SDAP) sublayer. The main services and
functions of SDAP may include providing a mapping between a QoS
flow and a data radio bearer and marking a QoS flow ID (QFI) in
both DL and UL packets. A single protocol entity of SDAP may be
configured for each individual PDU session. The SDAP sublayer may
support one or more of the following functions: transfer of user
plane data; mapping between a QoS flow and a data radio bearer
(DRB) for both DL and UL; marking QoS flow ID in both DL and UL
packets; and/or reflective QoS flow to DRB mapping for the UL SDAP
PDUs.
[0094] LTE and NR communications may employ logical channel
grouping. A logical channel group (LCG) may include a group of
LCH(s) or an equivalent where such grouping is based on one or more
criteria. Such criteria may include, for example, that the one or
more LCH(s) have a similar priority level applicable to all LCHs of
the same LCG (similar to legacy methods), or are associated with
the same type of transmissions, for example transmissions which
have a same SCS, duration, waveform or the like.
[0095] LTE and NR communications may employ Logical Channel
Prioritization (LCP) for UL transmissions. LCP may be used to
associate data available for transmission with resources available
for uplink transmissions. Multiplexing of data with different QoS
requirements within the same transport block may be supported as
long as such multiplexing neither introduces a negative impact to
the service with the most stringent QoS requirement nor introduces
unnecessary waste of system resources. The multiplexing may be
preferable when the WTRU is configured with a grant for a low
priority service and has data available for a higher priority
service, for example, an eMBB configuration when URLLC traffic is
available for transmission.
[0096] When assembling a MAC PDU, including when filling a TB with
data for an UL transmission, the WTRU typically serves data from
one or more LCH(s). The WTRU typically performs LCP with up to two
rounds. In a first round, equivalent to steps 1 and 2), data from
logical channels may be taken up to Prioritized Bit Rate (PBR) in
decreasing priority order. In step 2, the WTRU typically decrements
Bj by the total size of MAC SDUs served to logical channel j in
Step 1. Data may exceed the available amount of data for the LCH
for transmission in a given TTI (i.e., the "bucket"), typically to
avoid unnecessary RLC segmentation. In a second round,
equivalently, step 3, data from logical channels may be taken in
strict decreasing order to fill the remaining resources.
[0097] The term "bucket" will be understood by one skilled in the
art as a metaphor and may not necessarily be implemented by any
particular data structure or memory format. For example, a bucket
may be used to represent a quantity of data with which a WTRU may
transmit at any given time instant or during a time period. The
bucket may be implemented by decrementing a value upon
transmission, i.e. the buffer is emptied. The bucket may be
incremented upon a time period elapsing in which either no
transmission is made or in which a transmission is made which uses
less than a given quantity of data. There may be multiple buckets,
for example, two or more buckets used for each logical channel.
[0098] LTE and NR communications may employ transport channels
(TrCHs). A TrCH may include a specific set of processing steps
and/or a specific set of functions applied to data information that
may affect one or more transmission characteristics over the radio
interface. Multiple types of TrCHs may be supported, including, for
example, the Broadcast Channel (BCH), the Paging Channel (PCH), the
Downlink Shared Channel (DL-SCH), the Multicast Channel (MCH), and
the Uplink Shared Channel (UL-SCH), in addition to the Random
Access Channel (which typically does not carry any user plane
data). The DL-SCH and the UL-SCH, for the downlink and for the
uplink, respectively, may be considered as main transport channels
for carrying user plane data. Other channels may include a common
control channel (CCCH), dedicated control channel (DCCH) or
dedicated traffic channel (DTCH).
[0099] LTE and NR communications may employ QoS-Based parameters.
The WTRU may be configured with one or more parameters associated
with a characterization of how data should be transmitted. Such
characterizations may represent constraints and/or requirements
that the WTRU is expected to meet and/or enforce. The WTRU may
perform different operations and/or adjust its behavior as a
function of the state associated to the data based on such
characterization. Such parameters may include, but not be limited
to, time-related aspects, for example, Time to Live (TTL) for a
packet, which represents the time before which the packet should be
transmitted to meet, acknowledged, etc. to meet latency
requirements, rate-related aspects, and/or configuration related
aspects including an absolute priority. Such parameters may also be
changed with time while the packet or data is pending for
transmission. In some embodiments, QoS may be based on a 5G QoS
Identifier (5QI), a quality class indicator (QCI) or a pro-se per
packet priority (PPPP) in the case of proximity services or
sidelink transmission. A flow or bearer may be identified using a
QoS flow identifier (QFI) and reflective QoS may be indicated using
a reflective QoS indicator (RQI).
[0100] Flow Priority Indicator (FPI) and Flow Priority Level (FPL)
parameters may be included in the QoS framework definition for NR.
FPI may define priority per flow treatment at user plane (UP) and
access network (AN) functions and may correspond to scheduling
priority as well as priority handling in the case of congestion.
The FPI may differentiate between traffic flow aggregates mapped to
the same QCI and may also indicate whether the flow requires a
configured guaranteed flow bitrate and/or maximum flow bitrate. The
FPL may define the flow's relative importance to access an AN
resource. Further, the FPL may indicate whether the access to AN
non-prioritized resources should be pre-emptable and whether
resources allocated should be protected from pre-emption. A QoS
policy may include at least one of an FPI, FPL,
prioritize/guaranteed/aggregated bit rate, packet loss rate, packet
delay budget (PDB), maximum transmission delay, jitter,
inter-packet delay or the like.
[0101] One example characteristic of a Delay Critical Guaranteed
Bit Rate (GBR) flow is the Maximum Data Burst Volume (MDBV). The
MDBV may represent the largest amount of data that the access
network is required to serve for a given flow within a period of
PDB which period may correspond to the delay of the data while in
the access network itself.
[0102] A WTRU may transmit data units corresponding to user or
control plane traffic associated with flows having different QoS
requirements. A WTRU may have access to resources or different sets
thereof and/or processing functions or chains thereof that offer or
exhibit different service characteristics from the perspective of
QoS enforcement and/or guarantees. The WTRU may determine how to
associate data units with such resources and/or processing
functions as part of the logical channel prioritization (LCP)
function.
[0103] Some embodiments relate to how an access network may enforce
a Maximum Data Burst Volume (MDBV). It may be expected that the gNB
will use the MDBV within the radio admission control to determine
how delay critical GBR bearers may be supported in a cell
concurrently. With GBR bearers, the RAN provides some form of QoS
guarantees that a flow will be served with at least the guaranteed
bitrate; however, flows and applications may send at a higher rate
than the GBR for some reason including, for example, codec rate
adaptation, misbehaving implementations or the like. In such cases,
the network may account for statistical variations when performing
admission control thereby reducing the number of Delay Critical GBR
bearers served in a cell, as well as other bearers. For example, a
WTRU may be denied access if the number of Delay Critical GBR
bearers exceeds a configured threshold. Alternatively, a WTRU may
be instructed to only instantiate X flows, which may be based on a
gNB threshold.
[0104] Some embodiments relate to network enforcement of a MDBV and
a maximum rate over a period which may be a longer period than is
configured in LTE. Such enforcement may enable the network to
efficiently perform admission control and enforce MDBV for Delay
Critical GBR bearers. These embodiments may include modifications
to the behavior and/or configuration of a WTRU. These embodiments
may include signaling enhancements to the PHY, MAC, RLC layers or
higher layers.
[0105] The network may generally police and/or shape traffic for
different bearers. Shaping and policing may be useful to reduce or
minimize the impact of delay tolerant flows to Delay Critical GBR
flows and/or their respective impacts in between such flows of
similar priorities. This also may be useful to increase or maximize
cell capacity.
[0106] Network elements may be configured with tools and a flexible
implementation including a scheduler to control the multiplexing
functions for uplink transmissions of one or more WTRUs. For
example, a scheduler implementation may benefit from prioritizing a
particular flow in LCP step one but may limit the priority during
shaping performed in step 3 or ensuring any resource it takes in
step 3 does not impact other flows irrespective of priority. This
is referred to as policing. Policing may also apply at other steps,
including step 1 and step 2.
[0107] Some implementations may include modified or additional
buckets utilized at LCP. A short-term bucket to enforce PBR and a
long-term bucket to enforce MDBV may be combined, in embodiments,
to ensure transmission fairness. Some embodiments consider a bucket
state for the LCH in absolute prioritization, using either the
bucket related to the PBR or an equivalent, to the MDBV or an
equivalent or both. Having an additional bucket may have an added
benefit of controlling traffic in the short term, for example,
using a higher rate PBR and a certain bucket size. In the long
term, traffic may be controlled in the case of irregular traffic
arrivals, for example, by using a lower rate PBR. Parameters
corresponding to each of the short term bucket and the long term
bucket may be configured via DCI, MAC or RRC signaling.
[0108] Without limiting the applicability of the methods and
devices described herein, such methods and devices are applicable
to LCP functions involved in the selection and/or multiplexing of
data from bearers for uplink transmission in a wireless or wired
system, such as LTE or NR. The methods may also be applicable from
the perspective of a base station or TRP for downlink
transmission(s) to a WTRU as well as for sidelink transmissions
from WTRU to WTRU. In some embodiments, for example, remote radio
heads and relay nodes may be subjected to similar prioritization
problems as WTRUs.
[0109] In some embodiments, a WTRU may be configured with one or
more LCHs, where an LCH may be further configured with a plurality
of buckets, for example, two buckets. After being configured with a
number of buckets and applicable bucket parameters, a WTRU may
perform a LCP procedure where at least one logical channel (j) is
associated with at least one additional bucket of the plurality of
configured buckets. Additional buckets may be applicable to all or
subset of steps within the resource allocation procedure.
[0110] Such approaches may enable proper treatment of a traffic
flow that may have multiple QoS characteristics or requirements
over different time scales. These multiple QoS characteristics may
change over time or may be elements of a single QoS metric. An
example of such flow is a delay critical GBR QoS flow that has both
a guaranteed flow bit rate (GFBR) applicable on a long-term basis
and a maximum data burst volume (MDBV) applicable over a short-term
duration corresponding to the packet delay budget (PDB). Each
bucket may be used to determine whether the traffic served for a
logical channel would meet or exceed a bit rate requirement over a
specific time scale. Without loss of generality, it will be assumed
for the following examples that logical channel j is associated
with two (2) buckets, denoted Bj and B'j (or in some cases,
C.sub.j). Three or more buckets may also be configured in
accordance with the embodiments disclosed herein.
[0111] The WTRU may set an additional bucket B'j according to at
least one of the following: (1) the bucket B'j may be initialized
to zero (0) when the logical channel is established and may be
incremented upon some condition(s) before transmission is allowed.
Alternatively, the bucket B'j may be initialized to a value
corresponding to (PBR'.times.BSD') to ensure that prioritization
may be applied immediately upon logical channel establishment. The
initialization value may also be configured to be less than a
maximum value. (2) The bucket B'j may be incremented at a rate of
PBR' where PBR' represents an additional prioritized bit rate
parameter that may be set to a different value than the PBR
associated with the first bucket Bj. In other words, B'j may be
incremented by the product (PBR'.times.T) if T is the time interval
between two updates of B'j. Incrementing the bucket may be
performed linearly or at a rate which is greater than or less than
linear. (3) Each bucket may be incremented using the same time
interval T, or using a bucket-specific time interval Tj and Tj if
configured. In some embodiments, T may further represent a minimum
amount of time that may have elapsed before the WTRU may update the
concerned bucket. (4) The bucket B'j may have a maximum value of
(PBR'.times.BSD'), where BSD' represents an additional bucket size
duration parameter that may be set to a different value than the
BSD associated to the first bucket.
[0112] In an example, the WTRU may be configured according to one
of the following: (1) The WTRU may determine that there is a single
bucket for a given LCH (or LCH type), by default, if the
configuration of a second bucket is not present in a configuration
message, received via RRC for example. In such cases, the WTRU may
consider whether or not a second bucket is configured in the LCP
procedure to determine what, if any, further actions to take. (2)
The WTRU may determine that there are two buckets for a given LCH
or LCH type by default, independently of whether or not a
configuration for a second bucket is present in the configuration
message. If such a configuration is not present, the WTRU may
configure the second bucket with a set of default parameters, for
example, the value of the concerned bucket may be "infinite", or
any other suitable parameter. In such cases, the absence of a
configuration of a second bucket may not restrict the steps for
which the concerned bucket is applicable.
[0113] The parameters PBR', BSD' and optionally T' may be obtained
from MAC signaling, for example via a MAC CE. Alternatively or in
combination, the parameters may be configured by higher layers
including an RRC layer. When executing an LCH prioritization
procedure using two buckets for at least one LCH, the WTRU may
serve LCHs based on at least one of the following principles:
allocation up to the minimum (or maximum) values of the buckets: In
some embodiments, in an allocation step (such as the first
allocation step), an LCH configured with two buckets may be
allocated resources based on the minimum value across the buckets.
In other words, in an LCH, j may be allocated resources only if
both buckets Bj and B'j are positive. In some embodiments, an LCH,
j, may be allocated resources which do not exceed either bucket or,
alternatively, may be allocated resources which represent a
configured minimum even though the buckets may be positive (or may
be empty). Other LCHs configured with a single bucket may be
allocated resources based on the value of this bucket as usual, for
example, within the same allocation step, based on priority. Such
approaches may permit prioritization such that the corresponding
flow is not served in priority if the short-term bit rate would
exceed a short-term bit rate requirement, for example, an MDBV over
PDB requirement, or if the long-term bit rate would exceed a
long-term bit rate requirement, for example, GFBR. In some
embodiments, the values of two buckets Bj and B'j may be
decremented by the total size of MAC service data units (SDU)
served to the associated LCH j.
[0114] FIG. 2 is a timing graph 200 which shows an example of
values of buckets Bj 202 and B'j 204 as they evolve over time.
Referring to FIG. 2, the x-axis represents time 206 and the y-axis
represents bucket size 208. Initially, bucket Bj 202 represents
PBR.times.BSD 212 and B'j 204 represents PBR'.times.BSD' 210.
Initially, both buckets Bj 202 and B'j 204 are set at a maximum
level, i.e. Bj 202 is initialized at maximum level 214 and B'j 204
is initialized at maximum level 216. Both maximum values may be the
same or different values. Initialization values may be provided via
RRC, MAC, DCI and/or may be preconfigured or received via a higher
layers, for example, an application layer. In the example shown,
both buckets remain constant for a period prior to T0 218. At time
T0 218, logical channel j is served. When the logical channel j is
served, in this embodiment, both buckets are completely emptied.
Bucket Bj 202 fills in time T0+BSD 220, while bucket B'j 204 fills
at time T0+BSD' 222. The fill rates may be linear, as shown, or
alternatively may fill at other faster or slower rates, for
example, at exponential rates. Both buckets are completely filled
by time T0+BSD' 222. In an embodiment, a transmitter may transmit
at a rate in accordance with a minimum bucket size of either size.
Other transmit rates may be used.
[0115] In the example shown in FIG. 2, at time T0 218, both buckets
Bj 202 and B'j 204 have an equal effect on transmission size
because both buckets are initially of a same value and decrease at
a same rate. However, a distinction should be noted with respect to
the time period between T0 218 and time period T0+BSD 220. At any
time during this time period, if a buffer of the logical channel j
were to become non-empty, the WTRU may select data for transmission
based only upon bucket Bj 202. This is because, at all instances in
this time period, aside from T0 218, bucket B'j 204 has a value
which is lower than the value of Bj 202. Thus, bucket B'j 204 has a
limiting effect on the transmitter during this time period.
[0116] Similarly, in the time period T0+BSD 220 to T0+BSD' 222,
bucket B'j 204 has a lower value bucket Bj 202 at time instances
other than T0+BSD' 222 in which the two values are equivalent.
Thus, bucket B'j 204 may remain as the limiting bucket for the
transmission buffer of the WTRU for time period T0+BSD 220 to
T0+BSD' 222.
[0117] In some embodiments, an LCH configured with two buckets may
be allocated resources based on the maximum value across the
buckets. Such approaches may permit serving the corresponding flow
in priority if the bit rate over at least one time period,
short-term or long-term, would not exceed an associated
requirement. In some embodiments, the values of two buckets Bj and
B'j may be decremented by the total size of MAC SDU served to the
associated LCH j. In some embodiments, these values may be floored
to zero (0).
[0118] FIG. 3 is a timing graph 300 which illustrates another two
bucket example. In this example, both buckets 306, 308 affect an
amount of data transmitted at various points in time. The x-axis
represents time (in ms) 302 and the y-axis represents a data size
(in bytes) 304. Bucket 1 306 is configured with a 100 byte size and
bucket 2 308 is configured with a 20 byte size. In this example,
bucket 1 306 is filled (incremented) over 100 ms, while bucket 2
308 is filled much quicker, i.e. over 2 ms. Thus, bucket 1 306
fills at a rate of 100 bytes/100 ms or 1 byte per ms. Bucket 2 308
fills at a rate of 20 bytes over 2 ms or 10 bytes per ms. In this
way, bucket 2 308 may never fall below 10 bytes since with each
passing time instant, bucket 2 308 increases at a rate of 10/20
bytes, i.e. bucket 2 308 becomes at least half filled with each
passing time instant.
[0119] As shown in FIG. 3, both buckets 306, 308 are initialized
full, i.e. bucket 1 306 is initialized at 100 bytes and bucket 2
308 is initialized at 20 bytes. At time 320, 20 bytes of buffered
data 310 becomes available for transmission and the 20 bytes are
subsequently transmitted. This causes bucket 2 308 to drop 322 and
subsequently resume 324 to a full state within 2ms. Similarly,
bucket 1 306 drops 326 and more slowly resumes until time 328 in
which buffered data 310 again becomes available for transmission.
The data transmission of the newly buffered data begins at 20 bytes
in one transmission 330 and subsequently falls to a period 332 in
which only 10 bytes are transmitted at a time. During this period,
bucket 1 is decremented 334 until eventually all buffered data is
transmitted and no more data in buffer 310 remains. Subsequent to
time 336, bucket 2 308 completely fills by time 338, yet bucket 1
306 only reaches a local maximum at time 340. This is due to 50
bytes of data becoming available in the buffer by time 342. Upon
transmitting, the WTRU only transmits data up to the bucket size of
bucket 1 306. Bucket 1 306 is subsequently decremented by the same
amount to become empty at time 344.
[0120] During time period 346, bucket 1 306 is shown constant at 1
byte due to the empty bucket being incremented by 1 byte every ms
and subsequently decremented upon transmission of the byte.
Similarly, in the same period, the data in buffer 310 decreases 348
until no more data is available at time 350. During the remaining
time shown, bucket 1 306 increments linearly 352 at 1 byte per ms
as no new data enters the bucket.
[0121] It should be noted that bucket 2 308 has remained at full
fill since time 338 even though the WTRU has transmitted data. This
is due to the fact that bucket 1 306, in each subsequent
transmission instant, always remained below 20 bytes, i.e. the
capacity of bucket 2 308. Shaper 314 follows the minimum of bucket
1 306 and bucket 2 308. In an embodiment, data transmitted 312 will
never exceed shaper 314.
[0122] In some embodiments, the WTRU may, after each allocation
step, decrement the values of all buckets by the total size of MAC
SDU served to the associated LCHs during the step. Alternatively, a
smaller value may be decremented on a condition that the network is
experiencing load which is below a configured threshold. Similarly,
the value may be incremented quicker in the same circumstance. In
some embodiments, an allocation step may be performed only if
resources remain after completion of a previous allocation
step.
[0123] Some embodiments provide methods and devices for
prioritization using negative buckets. This may include, for
example, strict bucket enforcement and loose bucket enforcement. In
strict bucket enforcement techniques, MDBV may be strictly enforced
by not allocating resources in step 1 or step 3 beyond one or more
LCH bucket size, or beyond a slightly negative value to provide
some leeway to allow whole SDUs to be transmitted without
segmentation. This may alleviate subsequent small transmissions at
a cost of not strictly performing bucket enforcement. In such
cases, the WTRU may benefit from a proper configuration of the
applicable PBR(s) and bucket size(s) to minimize and/or avoid
excessive buffering at the WTRU. Strict enforcement may be applied
to the LCP procedure by considering whether the bucket(s) is or are
positive in all LCP steps, as well as subtracting the size of the
MAC PDUs allocated in all steps from the bucket(s). Examples of
strict bucket enforcement are discussed herein relating to single
bucket, dual bucket and multiple bucket techniques.
[0124] In some embodiments, the WTRU may determine that an LCH may
be served in LCP step 3 if, or if and only if, at least one of the
bucket(s) applicable to the concerned LCH is non-negative, for
example, B.sub.j in case of a single bucket, B.sub.j and C.sub.j in
case of dual buckets. In some embodiments, the WTRU may subtract an
amount, for example, the amount of data served in a MAC PDU in the
LCP step 3 from the buckets applicable for the concerned LCH. In
some embodiments, the WTRU may subtract the amount of data served
in a MAC PDU in the LCP step 3 from a single bucket, for example,
bucket C.sub.j in case of two buckets, in order to only impact the
limitation enforced by the concerned bucket, e.g., the long term
allowed data rate.
[0125] Strict enforcement of MDBV requirements in both step 1 and
step 3 may lead to resource waste in step 3. This may be the case
when the WTRU has no other LCH that may be served using the
concerned resources. This may occur if the remaining grant size is
larger than the amount of data allowed to be transmitted in step 3
considering strict enforcement. Accordingly, non-strict or "loose"
enforcement may be realized by decrementing bucket(s) corresponding
to the LCHs in step 3 as well. The LCP implementation may allow
resource allocation even if the bucket(s) is or are empty or
negative, including resource allocation in LCP step 3. The amount
of resources allocated in step 3 may therefore be subtracted from
the bucket(s), and the bucket(s) may be negative in value. Examples
of loose enforcement are further discussed herein with respect to
one, two or multiple buckets.
[0126] Changes in prioritization may occur on a dynamic basis. For
example, a WTRU may be configured to determine the priority of an
LCH and may perform such determination for a given period. The WTRU
may determine the priority of data associated to an LCH before it
determines what LCH may be considered in the LCP process. In some
cases, the WTRU may perform such determination for different steps
of the LCP process. The WTRU may be configured to determine that it
should use a specific priority value for an LCH and/or that such
priority has changed. The WTRU may perform such determination
following the occurrence of some event. Such events may be
application specific, protocol specific or may include NW
signaling.
[0127] In the case of NW signaling, for example, the WTRU may
receive downlink control signaling including a downlink control
information (DCI), a MAC control element (CE) or a RRC PDU. Such
signaling may indicate that the priority of an LCH may be changed
and may be set to a specific value, lowered, increased, set to a
highest value, set to a lowest value or the like. Alternatively,
such signaling may indicate one or more other parameters for a
given LCH, for example, a PBR value, a PSD value or the like.
Alternatively, such signaling may activate and/or configure an
additional bucket, for example, C.sub.j for activating a dual
bucket processing. Alternatively, such signaling may indicate that
the WTRU should refrain from serving data from a specific LCH. In
this way, the WTRU may consider service for the LCH to be
suspended. Such signaling may include a period during which the
change is valid, after which, the WTRU may revert to the set of
parameters previously applicable.
[0128] A priority of a LCP may be lowered or increased using a
fixed value, for example, -2, -1, +1, +2 or the like.
Alternatively, the WTRU may maintain a table of priority values for
which the NW may signal an identifier such that the WTRU may select
a given priority. In some embodiments, the WTRU may select a change
in priority value in an autonomous fashion, based in part on
application layer demands, measurements, handover or the like.
[0129] Such events may include the elapse of a time period, or a
time-related state of the LCH. For example, the WTRU may make the
determination based on a timer such as a suspendLCH-timer, a
prohibitLCH-timer or a burstLCH-timer. Such events may include a
function of the servicing state of the LCH. For example, the WTRU
may determine that a bucket for the LCH is empty, zero or negative;
that a PBR is satisfied for the LCH; and/or that data for the LCH
may be multiplexed in a MAC PDU.
[0130] Such events may include a function of a configured aspect. A
function may include a mapping of priorities to mapping
restrictions. For example, the WTRU may determine the priority of
data associated to an LCH as a function of the mapping
restrictions. For example, the WTRU may be configured with mapping
restrictions such that if one or more mapping criteria are met, the
WTRU may consider the LCH in the LCP procedure. For a given
transmission step, the WTRU may use different priority rules. For
example, for one step, the WTRU may use a first priority value,
while the WTRU may use a second priority value for one or more
other steps.
[0131] Such events may include a function of the per-packet QoS
including a QFI, or based on another field of the SDAP. For
example, the WTRU may determine the priority of data associated to
an LCH as a function of the QoS priority associated with a data
unit. For example, the WTRU may determine a priority level for data
served for a given LCH as a function of the QFI field in the SDAP
header of a packet for transmission. The association between a
priority for the LCH and a QFI value may be a configuration aspect
of the WTRU. As the QFI value changes, an associated priority of
the LCH may change accordingly.
[0132] Such priority changes may be applicable until a next event
that again changes the priority of an LCH. Such priority changes
may be applied for all steps of the LCP processing, only for the
step based on satisfying PBR in step 1, only for step 3 based on
absolute prioritization or for both steps.
[0133] In some embodiments, the priority order may depend on the
allocation step. This approach may improve fairness between LCHs of
a single device. The priority order applicable to an allocation
step may depend on the outcome of a previous allocation step. For
example, it may depend on the value of a bucket, for example, the
bucket with the highest value for an LCH configured with two
buckets. For example, the WTRU may prioritize LCHs with highest
non-empty buckets among LCHs configured with two buckets. The
priority order applicable to a specific allocation step may be
configured by higher layers via MAC or physical layer (PHY) layer
signaling. The priority order applicable to a specific allocation
step may depend on the number of buckets configured for the LCH.
For example, LCHs configured with two buckets may have higher
priority than LCHs configured with a single bucket. The order of
priority may depend on the allocation step. For example, LCHs
configured with two buckets may have higher priority than LCHs
configured with a single bucket in a first allocation step, and may
have lower priority than LCHs configured with a single bucket in a
subsequent allocation step. The priority order may depend on a
property of the resource, such as a serving cell, an UL carrier (UL
or supplementary UL), a PUSCH duration, a type of grant (dynamic or
configured, type 1 or type 2). The priority order may depend on
whether the logical channel is associated to a bearer for which
PDCP duplication is configured or activated. For example, a
transmission on a supplementary UL carrier may have a higher or
lower priority than a transmission on a regular UL carrier. In some
embodiments, a timing aspect may be considered. If, for example, a
SUL was recently activated, a priority of the SUL may be greater
than or less than the priority of the RUL.
[0134] A prioritization for PBR-based multiplexing may change
dynamically. For example, regarding step 1, the WTRU may be
configured to determine that the priority of an LCH should be
modified upon the occurrence of a specific event, such as one of
the examples described above. The WTRU may determine, for example,
that the priority of an LCH may be decreased to a configured value,
or to the lowest priority only for the step based on satisfying PBR
as in step 1. This may be useful to ensure that overprovisioning of
granted resources for a WTRU may be available to other GBR bearers
of equal or lesser priority.
[0135] Absolute prioritization may change dynamically. For example,
regarding steps 2 and 3 as discussed herein, the WTRU may be
configured to determine that the priority of an LCH should be
modified upon the occurrence of a specific event, such as one
described above. In one example, the WTRU may determine that the
priority of an LCH may be decreased to a configured value, or to
the lowest priority only for step 3 which is based on absolute
prioritization. This may be useful to ensure that overprovisioning
of granted resources for a WTRU may be available to other non-GBR
bearers of possibly equal or lesser priority.
[0136] Some embodiments relate to time-based multiplexing
restrictions. For example, the WTRU may be configured to determine
whether an LCH may be served or not for a transmission as a
function of a state of the LCH. Such states may include an active
state or suspended states and may be controlled as a function of
time. In cases where LCH is configured with multiple buckets, such
may correspond to the short-term prioritized rate e.g., the maximum
burst data volume. The WTRU may perform such determinations for all
steps of the LCP procedure or for less than all steps.
[0137] The WTRU may be configured with a timer such as a
suspendLCH-timer. RRC may configure an initial value for the timer.
Such timers may be configured for a given LCH. The WTRU may serve
the associated LCH for any steps of the LCP procedure when the
timer is not running, has stopped, or has expired. In such cases,
the LCH may not contend for any resource in LCP for some periods.
Thus, in these periods, the LCH may be suspended. In some
embodiments, the WTRU may start the timer if the WTRU determines
that the bucket for the LCH is empty, zero or negative; if the WTRU
determines that the PBR is satisfied for the LCH; if the WTRU
determines that data for the LCH may be multiplexed in a MAC PDU; a
combination of any of these; and/or if the WTRU receives downlink
control signaling that starts, restarts or stops the timer.
[0138] In some embodiments, the WTRU may be configured to determine
whether an LCH may be served or not for a transmission as a
function of a bucket state. In case of an LCH configured with
multiple buckets, this may correspond to the short-term prioritized
rate including the maximum burst data volume. The WTRU may perform
such determination for step 3 which is based on absolute
prioritization.
[0139] The WTRU may be configured with a prohibitLCH-timer timer so
as to prohibit an LCH process for a period of time. An initial
value for the prohibitLCH-timer or any other timer may be
configured via the RRC layer or another layer. One or more timers
may be configured for a given LCH. The WTRU may serve the
associated LCH for step 3, i.e. the step based on absolute
prioritization, when the timer is not running, has stopped or has
expired. In such cases, the LCH may not contend in the absolute
priority-phase of LCP for some periods. In some embodiments, the
WTRU may start the timer based on: whether or not the WTRU
determines that the bucket for the LCH is empty, zero or negative;
whether or not the WTRU determines that the PBR is satisfied for
the LCH; whether or not the WTRU determines that data for the LCH
may be multiplexed in a particular MAC PDU; a combination of any
the above; or if the WTRU receives downlink control signaling that
starts, restarts or stops the timer. Alternatively, a similar
method may be applied only for determination of whether or not an
LCH may be served in the step based on satisfying PBR in step 1. In
such cases, the LCH may not contend in the PBR-phase of LCP for
some periods which may also be controlled by a timer. In some
embodiments, the WTRU may not update the concerned buckets while
the timer is running.
[0140] The WTRU may be configured to determine whether an LCH may
be served or not for a transmission as a function of the time
elapsed since it was last served, since its PBR was last met, or
since its bucket was last zero or negative. In cases where an LCH
is configured with multiple buckets, this may correspond to the
short-term prioritized rate, for example, the MBDV rate. In some
embodiments, the WTRU may perform such determinations only for the
step based on satisfying PBR (e.g., step 1), only for the step
based on absolute prioritization (e.g., step 3), or for both.
[0141] The WTRU may be configured with a burstLCH-timer timer.) RRC
layer signaling may configure an initial value for the timer and/or
a periodically updated value for the timer. Such timers may be
configured for a given LCH. The WTRU may serve the associated LCH
when the timer is not running, has stopped or has expired. The WTRU
may start the timer based on: if the WTRU determines that the
bucket for the LCH is empty, zero or negative; if the WTRU
determines that the PBR is satisfied for the LCH; if the WTRU
determines that data for the LCH may be multiplexed in a MAC PDU; a
combination of any of the above; or if the WTRU receives downlink
control signaling that starts, restarts or stops the timer. In some
embodiments, the WTRU may not update the concerned buckets while
the timer is running. Alternatively, one of the buckets may be
updated while other buckets are not.
[0142] Some embodiments relate to determination of LCH applicable
for prioritization. For example, a WTRU may determine whether an
LCH is applicable or not to a specific LCP prioritization round as
a function of whether the LCH is configured with a single bucket or
whether the LCH is configured with multiple buckets. For example,
the WTRU may determine that an LCH configured with a second bucket
may be considered in a first round using a PBR-based prioritization
using a first bucket, in a second round using PBR-based
prioritization using a second bucket, but not in a third round of
prioritization using absolute prioritization.
[0143] In some examples, the WTRU may determine whether an LCH is
applicable or not to a specific LCP prioritization round as a
function of a state of a bucket. For example, the WTRU may
determine that an LCH configured with a second bucket may be
considered in a first round using PBR-based prioritization using a
first bucket if the first bucket is non-negative, in a second round
using PBR-based prioritization using a second bucket if the second
bucket is non-negative and in a third round of prioritization using
absolute prioritization if the second bucket is non-negative.
[0144] Additional LCP prioritization rounds may be performed for
rate limiting purposes. For example, a WTRU may perform one
additional round of prioritization or one or more additional steps
in the LCP procedure according to any one or more of the methods
described herein. In some embodiments, an additional allocation
step is introduced into the procedure if at least one LCH is
associated with two buckets. Such additional allocation steps may
be used, for example, to apply different prioritizations between
LCHs configured with two buckets and LCHs configured with a single
bucket.
[0145] FIG. 4A is a flowchart 400 illustrating a first resource
allocation method. In an example procedure, the following steps may
be performed. Resources may be allocated 402 only to LCHs
configured with two buckets, up to the value of a first bucket.
Such bucket may be a specific bucket (e.g. always Bj or always
B'j), or may be the bucket with the minimum value. Resources may be
allocated 404 to all LCHs, up to the value of the bucket for an LCH
configured with a single bucket or up to the value of the second
bucket for an LCH configured with two buckets. Resources may be
allocated 406 to all LCHs up to their remaining available data.
Such example procedures implicitly prioritize LCHs configured with
two buckets, which, in general, may be expected to correspond to
delay-critical guaranteed bit rate flows. Any one or more of these
steps may not be employed in some embodiments and an ordering of
these steps may vary in accordance with an embodiment.
[0146] FIG. 4B is a flowchart 410 illustrating a second resource
allocation method. In this example procedure, one or all of the
following steps may be performed. Resources may be allocated 412
only to LCHs configured with two buckets, up to the value of a
first bucket. Such bucket may be a specific bucket, for example,
always Bj or always B'j, or may be the bucket with the minimum
value. Resources may be allocated 414 only to LCHs configured with
a single bucket, up to the value of the bucket. Resources may be
allocated 416 only to LCHs configured with two buckets, up to the
value of the second bucket. Resources may be allocated 418 to all
LCHs up to their remaining available data. Such example procedures
implicitly prioritize LCHs configured with two buckets with respect
to meeting their minimum requirement. However, LCHs with single
bucket are served next to prevent a situation where all resources
would be monopolized by the LCHs configured with two buckets. Any
one or more of these steps may not be employed in some embodiments
and an ordering of these steps may vary in accordance with an
embodiment.
[0147] The WTRU may further apply the following: After each
allocation step, the values of all buckets may be decremented by
the total size of the MAC SDU served to the associated LCHs during
the step. An allocation step may be performed if and only if
resources remain after completion of a previous allocation
step.
[0148] In another example, the WTRU may be configured to perform a
first prioritization round in step 1 for PBR-based prioritization
using a first PBR configuration having a first bucket Bj, by
considering an applicable LCH(s) as a function of their mapping
restrictions, if any, for that round. The WTRU may then perform a
second, an additional PBR-based prioritization using a second PBR
configuration, for example, using a second bucket Cj, by
considering only LCH(s) configured with a second bucket and
applicable as a function of their mapping restrictions. In some
embodiments, such LCH may be considered if and only if there are no
other LCH(s) configured with a single bucket and with a higher
priority. In this case, the WTRU may perform a third prioritization
round based on absolute prioritization in step 3. In this case, in
some embodiments, the WTRU may consider that any LCH configured
with more than one bucket should be assigned the lowest priority.
In some embodiments, such assignments may be only with respect to
LCH(s) configured with a single bucket, for example, the WTRU may
maintain the relative priorities between LCHs configured with
multiple buckets in that prioritization round.)
[0149] A buffer status reporting (BSR) and/or scheduling request
(SR) transmission may be made by a WTRU to request transmission
resources. For example, in some embodiments, if an LCH/LCG is on
hold, data is not considered available for transmission for the
LCH/LCG. In some embodiments, the WTRU may consider data as new
data available for transmission for the purpose of further
determination of whether or not an action, such as a trigger for
BSR and/or a scheduling request(SR) or any other available means to
acquire more resources should be initiated. A determination of an
applicable transmission method for a BSR and/or SR, may be made
according to at least one of the following. The WTRU may disable
triggering of BSR and/or of SR for an LCH that is suspended. In
some embodiments, the WTRU may perform such actions when the LCH
may not contend in the PBR-based step of the LCP procedure. (2) The
WTRU may consider a change in LCH priority, such as described,
herein, when it determines whether or not new data becoming
available for transmission should trigger transmission of the BSR
and/or SR.
[0150] Without limiting the applicability of the methods described
herein to specific implementations, embodiments, and/or
realizations, this section presents different realizations using
the LCP procedure described herein as a baseline.
[0151] Some realizations relate to strict negative buckets and
absolute prioritization. For example, the following illustrates one
example realization of an LCP procedure for an LCH configured with
a single bucket, whereby the WTRU enforces an absolute maximum rate
for a given flow:
TABLE-US-00001 Resource Allocation Procedure The MAC entity shall,
when a new transmission is performed: 1> allocate resources to
the logical channels as follows: 2> logical channels selected
for the UL grant with Bj > 0 are allocated resources in a
decreasing priority order. If the PBR of a logical channel is set
to "infinity", the MAC entity shall allocate resources for all the
data that is available for transmission on the logical channel
before meeting the PBR of the lower priority logical channel(s);
2> decrement Bj by the total size of MAC SDUs served to logical
channel j above; 2> if any resources remain, all the logical
channels selected with Bj > 0 are served in a strict decreasing
priority order until either the data for that logical channel or
the UL grant is exhausted, whichever comes first. Logical channels
configured with equal priority should be served equally. 2>
decrement Bj by the total size of MAC SDUs served to logical
channel j above; NOTE: The value of Bj may be negative.
[0152] Dual (or more) negative buckets and absolute prioritization
may be performed in some LCP procedures. For example, the following
text illustrates one example realization of an LCP procedure for an
LCH configured with dual buckets, whereby the WTRU enforce an
absolute maximum rate for a given flow:
TABLE-US-00002 General ... The following WTRU variables are used
for the Logical channel prioritization procedure: - Bj which is
maintained for each logical channel j; - Cj which is maintained for
each logical channel j for which PBR2 is configured. The MAC entity
shall initialize Bj of the logical channel to zero when the logical
channel is established. If PBR2 is configured, the MAC entity shall
initialize Cj of the logical channel to zero when the logical
channel is established. For each logical channel j, the MAC entity
shall: 1> increment Bj by the product PBR .times. T before every
instance of the LCP procedure, where T is the time elapsed since Bj
was last updated; 1> if the value of Bj is greater than the
bucket size (i.e. PBR .times. BSD): 2> set Bj to the bucket
size. For each logical channel j for which PBR2 is configured, the
MAC entity shall: 1> increment Cj by the product PBR2 .times. T
before every instance of the LCP procedure, where T is the time
elapsed since Cj was last updated; 1> if the value of Cj is
greater than the bucket size (i.e. PBR2 .times. BSD2): 2> set Cj
to the bucket size. ... Allocation of resources The MAC entity
shall, when a new transmission is performed: 1> allocate
resources to the logical channels as follows: 2> logical
channels selected above for the UL grant with Bj > 0 and Cj >
0 are allocated resources in a decreasing priority order. If the
PBR of a logical channel is set to "infinity", the MAC entity shall
allocate resources for all the data that is available for
transmission on the logical channel before meeting the PBR of the
lower priority logical channel(s); 2> decrement Bj and Cj (if
configured) by the total size of MAC SDUs served to logical channel
j above; 2> if any resources remain, all the logical channels
selected with Bj > 0 and Cj > 0 (if configured) are served in
a strict decreasing priority order until either the data for that
logical channel or the UL grant is exhausted, whichever comes
first. Logical channels configured with equal priority should be
served equally. 2> decrement Bj and Cj (if configured) by the
total size of MAC SDUs served to logical channel j above; NOTE: The
value of Bj or Cj (if configured) may be negative.
[0153] Loose negative buckets, for example, buckets which may have
low negative values may be realized with absolute prioritization in
some embodiments. For example, MDBV may be applied on a per period
basis, for example, on a TTI, during a transmission duration or for
a configured period, while relying on decrementing the LCH's
bucket(s) after step 3. A TTI, transmission duration or configured
period may vary in accordance with transmission and other network
parameters. An example of this is illustrated by the following text
for an LCP procedure for an LCH configured with two buckets. Cj is
removed for a single bucket implementation.
TABLE-US-00003 Allocation of resources The MAC entity shall, when a
new transmission is performed: 1> allocate resources to the
logical channels as follows: 2> logical channels selected for
the UL grant with Bj > 0 and Cj > 0 are allocated resources
in a decreasing priority order. If the PBR of a logical channel is
set to "infinity", the MAC entity shall allocate resources for all
the data that is available for transmission on the logical channel
before meeting the PBR of the lower priority logical channel(s);
2> if any resources remain, all the logical channels selected
are served in a strict decreasing priority order (regardless of the
value of Bj) until either the data for that logical channel or the
UL grant is exhausted, whichever comes first. Logical channels
configured with equal priority should be served equally. 2>
decrement Bj and Cj (if configured) by the total size of MAC SDUs
served to logical channel j above; NOTE: The value of Bj or Cj (if
configured) may be negative.
[0154] The negative value of the bucket(s) may be configured with a
minimum bucket level to ensure that the bucket does not go negative
to a degree that would starve the logical channel from
resources:
The value of Bj or Cj (if configured) may be negative, up to
MinimumLevel if configured.
[0155] A more lenient implementation of non-strict enforcement of
MDBV may penalize resource allocation in step 3 according to the
contents of the bucket(s) or according to the prioritized bit rates
configured for the buckets. For example, for each LCH configured
with MDBV enforcement, the amount decremented from the bucket(s) in
step 3 may be according to the following text. Cj may be removed
for single bucket LCHs.
TABLE-US-00004 decrement Bj and Cj (if configured) by the amount of
data allocated beyond PBR1 .times. T, where T is the time elapsed
since Bj was last updated; if Cj is configured, decrement Bj and Cj
by the amount of data allocated beyond Cj, if Bj is less than Cj
and Cj > 0;if Cj is configured, decrement Bj and Cj by the
amount of data allocated beyond Bj, if Cj is less than Bj and Bj
> 0; if Cj is configured, decrement Bj and Cj by the amount of
data allocated beyond |Bj - Cj|; decrement Bj and Cj (if
configured) by the total size of MAC SDUs served to logical channel
j, if other LCHs of lower priorities have buffered data;
[0156] The WTRU may apply these decrements, i.e. may decrement one
or a subset of the buckets, depending on the bucket contents for
example. The WTRU may apply these additional decrements subject to
a configured timer. For instance, the WTRU may apply additional
decrements in step 3 if one of the timers described herein is
running. Further, the WTRU may further penalize resource allocation
for an LCH on which MDBV is enforced if other logical channels with
buffered data were not allocated any resources in all or some steps
of the LCP procedure. For example, the additional step may be in
the following form:
decrement Bj and Cj (if configured) by the sum of Bjs of logical
channels with buffered data that were not allocated resources in
either step 1 or step 3;
[0157] A dynamic change in absolute prioritization may be realized.
The change may be based on the LCP of the LCH, based on the data
transmission, based on application layer information, based on
network signaling or the like. For example, non-strict enforcement
of MDBV requirements may be realized by changing LCH priorities in
certain step(s) of the LCP resource allocation procedure. For
example, after step 2, the priority of an LCH with MDBV enforcement
may be changed if one or more of the following apply: (1) Other
LCHs of lower priorities (or LCHs with no MDBV enforcement
configured) have buffered data. (2) Other LCHs of lower priorities
(or LCHs with no MDBV enforcement configured) were not allocated
any resources in step 1. (3) The LCH's bucket(s) are empty,
negative, or below a configured value. (4) The LCH is configured
with more than one bucket. (5) If Cj is less than the Bj and
PBR.sub.Cj>PBR.sub.Bj.
[0158] An example of such conditions may be illustrated by the
following step after step 2:
TABLE-US-00005 Other logical channels not configured with MDBV
enforcement have buffered data Other logical channels not
configured with MDBV enforcement were not allocated data Bj or Cj
(if configured) <= 0 Bj or Cj (if configured) < MinimumLevel
Cj < Bj and PBR2 > PBR 1, if PBR2 is configured Other logical
channels with lower priorities have buffered data Other logical
channels with lower priorities were not allocated data
[0159] A more dynamic prioritization may be performed in
embodiments, for example, by considering the bucket contents of
each logical channel. For example, logical channel priorities may
by adjusted dynamically prior to a given step in LCP, where
priorities, high to low, are assigned by descending order of Bj (or
min{Cj,Bj} if both are configured), by descending order of the
max{Cj, Bj}, if both are configured, and/or by descending order of
backlog (Bj plus the buffered data amount for the logical
channel).
[0160] For example, such may be illustrated by the adding the
following step after step 2:
Adjust logical channel priorities from high to low in descending
order of min{Bj, C.sub.j}
[0161] The WTRU may further apply LCH priority changes subject to a
configured timer. For example, the WTRU may apply LCH priority
changes in step 3 if one of the timers described herein is
running.
[0162] Time-based multiplexing restrictions may be considered in
LCP. For example, a WTRU may be configured such that it may not
update a bucket ahead of every instantiation of the LCP procedure.
This may be useful as a means for the network to further control
the filling of the bucket, thereby possibly shaping the traffic
patterns. For example, this may be useful to enforce burstiness for
a given flow, or to smoothen it. It may be useful for the NW to
enforce burstiness such that the SDU discard function of PDCP may
trigger SDU discard on some or any amount of data that exceeds the
MDBV. In such cases, the NW scheduler may serve the LCH up to its
PBR in step 1 while precluding the LCH from contending for
resources in other steps, for example, step 3. In that manner,
there may be less of a need for an additional bucket to enforce
MDBV for the purpose of precluding the flow from misbehaving in
terms of maximum rate. For example, such conditions can be
illustrated as per the following text:
TABLE-US-00006 The MAC entity shall initialize Bj of the logical
channel to zero when the logical channel is established. For each
logical channel j, the MAC entity shall: increment Bj by the
product PBR .times. T before every instance of the LCP procedure,
where T is the time elapsed since Bj was last updated. If a minimum
updating interval Tj is configured, T shall be set such that Bj is
incremented before the first instance of the LCP procedure such
that T >= Tj; 1> if the value of Bj is greater than the
bucket size (i.e. PBR .times. BSD): 2> set Bj to the bucket
size. NOTE: The exact moment(s) when the WTRU updates Bj between
LCP procedures is up to WTRU implementation, as long as Bj is up to
date at the time when a grant is processed by LCP.
[0163] Some realizations relate to logical channel prioritization
in NR MAC. For example, such realizations are illustrated by the
following:
TABLE-US-00007 Multiplexing and assembly Logical channel
prioritization General The Logical Channel Prioritization procedure
is applied whenever a new transmission is performed. RRC controls
the scheduling of uplink data by signalling for each logical
channel per MAC entity: - priority where an increasing priority
value indicates a lower priority level; - prioritizedBitRate which
sets the Prioritized Bit Rate (PBR); - bucketSizeDuration which
sets the Bucket Size Duration (BSD). RRC additionally controls the
LCP procedure by configuring mapping restrictions for each logical
channel: - allowedSCS-List which sets the allowed Subcarrier
Spacing(s) for transmission; - maxPUSCH-Duration which sets the
maximum PUSCH duration allowed for transmission; -
configuredGrantType1Allowed which sets whether a Configured Grant
Type 1 may be used for transmission; - allowedServingCells which
sets the allowed cell(s) for transmission. The following WTRU
variable is used for the Logical channel prioritization procedure:
- Bj which is maintained for each logical channel j. The MAC entity
shall initialize Bj of the logical channel to zero when the logical
channel is established. For each logical channel j, the MAC entity
shall: 1> increment Bj by the product PBR .times. T before every
instance of the LCP procedure, where T is the time elapsed since Bj
was last updated; 1> if the value of Bj is greater than the
bucket size (i.e. PBR .times. BSD): 2> set Bj to the bucket
size. NOTE: The exact moment(s) when the WTRU updates Bj between
LCP procedures is up to WTRU implementation, as long as Bj is up to
date at the time when a grant is processed by LCP. Selection of
logical channels The MAC entity shall, when a new transmission is
performed: 1> select the logical channels for each UL grant that
satisfy all the following conditions: 2> the set of allowed
Subcarrier Spacing index values in allowedSCS-List, if configured,
includes the Subcarrier Spacing index associated to the UL grant;
and 2> maxPUSCH-Duration, if configured, is larger than or equal
to the PUSCH transmission duration associated to the UL grant; and
2> configuredGrantType1Allowed, if configured, is set to TRUE in
case the UL grant is a Configured Grant Type 1; and 2>
allowedServingCells, if configured, includes the Cell information
associated to the UL grant. NOTE: The Subcarrier Spacing index,
PUSCH transmission duration and Cell information are included in
Uplink transmission information received from lower layers for the
corresponding scheduled uplink transmission. Allocation of
resources The MAC entity shall, when a new transmission is
performed: 1> allocate resources to the logical channels as
follows: 2> logical channels selected for the UL grant with Bj
> 0 are allocated resources in a decreasing priority order. If
the PBR of a logical channel is set to "infinity", the MAC entity
shall allocate resources for all the data that is available for
transmission on the logical channel before meeting the PBR of the
lower priority logical channel(s); 2> decrement Bj by the total
size of MAC SDUs served to logical channel j above; 2> if any
resources remain, all the logical channels selected are served in a
strict decreasing priority order (regardless of the value of Bj}
until either the data for that logical channel or the UL grant is
exhausted, whichever comes first. Logical channels configured with
equal priority should be served equally. NOTE: The value of Bj may
be negative. If the MAC entity is requested to simultaneously
transmit multiple MAC PDUs, or if the MAC entity receives the
multiple UL grants within one or more coinciding PDCCH occasions
(i.e. on different Serving Cells), it is up to WTRU implementation
in which order the grants are processed. The WTRU shall also follow
the rules below during the scheduling procedures above: - the WTRU
should not segment an RLC SDU (or partially transmitted SDU or
retransmitted RLC PDU) if the whole SDU (or partially transmitted
SDU or retransmitted RLC PDU) fits into the remaining resources of
the associated MAC entity; - if the WTRU segments an RLC SDU from
the logical channel, it shall maximize the size of the segment to
fill the grant of the associated MAC entity as much as possible; -
the WTRU should maximise the transmission of data; - if the MAC
entity is given a UL grant size that is equal to or larger than 8
bytes while having data available for transmission, the MAC entity
shall not transmit only padding BSR and/or padding. The MAC entity
shall not generate a MAC PDU for the HARQ entity if the following
conditions are satisfied: - the MAC entity is configured with
skipUplinkTxDynamic and the grant indicated to the HARQ entity was
addressed to a cell radio network temporary identifier (C-RNTI), or
the grant indicated to the HARQ entity is a configured uplink
grant; and - there is no aperiodic CSI requested for this PUSCH
transmission as specified in TS 38.212 [9]; and - the MAC PDU
includes zero MAC SDUs; and - the MAC PDU includes only the
periodic BSR and there is no data available for any LCG, or the MAC
PDU includes only the padding BSR. Logical channels shall be
prioritized in accordance with the following order (highest
priority listed first): - C-RNTI MAC CE or data from UL-CCCH; -
Configured Grant Confirmation MAC CE; - MAC CE for BSR, with
exception of BSR included for padding; - Single Entry PHR MAC CE or
Multiple Entry PHR MAC CE; - data from any Logical Channel, except
data from UL-CCCH; - MAC CE for BSR included for padding.
[0164] FIG. 5 is a flowchart 500 illustrating a method for
transmitting data using a long term token bucket and a short term
token bucket. A WTRU may associate a logical channel with a long
term bucket 502 and a short term bucket 504. The long term bucket
may be initialized 506 to a value which is greater than a value
used to initialize the short term bucket. A buffer, of the WTRU,
may become non-empty 508 and may include logical channel data of
the logical channel. The WTRU may transmit 510 a portion of the
logical channel data on the logical channel, in a TTI without
transmitting more than a minimum of a value corresponding to the
short term token bucket and the long term token bucket. Upon
transmitting data, the WTRU may decrement 512 the long term token
bucket and the short term token bucket so that each bucket may
further limit a subsequent transmission. If the buffer is empty
514, the long term bucket and the short term bucket may be
incremented 516 in each subsequent TTI for which data is not
transmitted so that the bucket values may rise back to an
initialized value. If the buffer is determined 514 to be non-empty,
the WTRU may consider transmitting 510 a next portion of the
logical channel data without transmitting more than a minimum of
either token bucket.
[0165] Although features and elements are described above in
particular combinations, one of ordinary skill in the art will
appreciate that each feature or element can be used alone or in any
combination with the other features and elements. In addition, the
methods described herein may be implemented in a computer program,
software, or firmware incorporated in a computer-readable medium
for execution by a computer or processor. Examples of
computer-readable media include electronic signals (transmitted
over wired or wireless connections) and computer-readable storage
media. Examples of computer-readable storage media include, but are
not limited to, a read only memory (ROM), a random access memory
(RAM), a register, cache memory, semiconductor memory devices,
magnetic media such as internal hard disks and removable disks,
magneto-optical media, and optical media such as CD-ROM disks, and
digital versatile disks (DVDs). A processor in association with
software may be used to implement a radio frequency transceiver for
use in a WTRU, UE, terminal, base station, RNC, or any host
computer.
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